Are you kidding me? Victorian Britain was the most prosperous country on Earth, at the time. Sure, the average Brit had it much rougher than they do today, but that's not a valid comparison. Give me one country that had it better during the 19th century than Victorian Britain!
Sure, they were more prosperous on average, but the poor were much more worse off than the poor in rural areas.
It's also impossible to say whether the prosperity was due to the free market and lack of regulations, the industrial revolution and development of steam power or the rise of the middle class and their increased free time/income.
I suspect that mostly it was technology, similar to what's happening in developing nations right now, rather than any free markets.
"the poor were much more worse off than the poor in rural areas."
Do you have any support for that assertion? The poor themselves decided en masse to move from village to city at the time, which seems to indicate the contrary. Yes, in the city they were also much more visible to literate observers who would write about their misery, but who knows what those same observers might have exposed if they had lived in a village instead. The people who knew both sides of the situation, certainly seemed to vote with their feet for the industrialized cities. We see the same phenomenon at work in China nowadays.
That's the standard Marxist analysis, but it's been refuted since, by Armstrong and others. The Enclosure Acts "kicked" very few people off the land. What they did mostly was to transform poorly utilized common land (marginal pasture, forests, and even some "tragedy of the commons"-style arable land) into extremely productive privately owned plots. The food production increased immensely as a result, which allowed bustling cities and industries to be well supplied. The general prosperity of society increased immensely, while previously starving peasants moved into the cities to become well-fed, but poorly-housed, poorly-clothed etc. workers (at least in the first generation). Even these deficiencies were remedied quite fast, and by the end of the Victorian period, manual laborers would commonly go around town dressed in what today we'd call a business suit.
I'm not arguing that the Enclosure Acts reduced the prosperity of society in aggregate, merely that one of their direct results was that "previously starving peasants moved into the cities" wasn't a free choice on the part of the peasants in many cases. They may have even ended up better off in doing so, but that's different from whether it was voluntary. I don't think you need a Marxist analysis to come to the conclusion that the Enclosure Acts didn't have a neutral effect on the pace of urbanization; it's what you find in standard mainstream histories from folks like Spielvogel as well.
Mostly I don't think it's at all clear that "being poor in the city working in a factory" would actually be preferred over "being a peasant farmer" given conditions of the time, if it were truly a free choice. In the United States at around the same time, you find many people choosing to leave cities to become subsistence farmers on the frontiers, because the Homestead Acts made it a viable option. If the UK had taken the enclosed land and distributed it via a Homestead-Act style process, would British peasants have chosen that option?
The comparison with the US is not appropriate, as we're talking about very different cadastral situations. The US has, at the time, a wide open western frontier, with enormous quantities of fertile arable land freely available. Britain is a country in which all the reasonably fertile land has long been brought under cultivation. Enclosures apply to marginal land (marshes, poor pasture), in which a few semi-squatting, destitute "cottagers" eke out a very desolate existence. This land can be made fertile, but only with a huge investment of capital (e.g. draining). The way the enclosure act works is that the cottagers are paid some meager compensation in exchange for their grazing rights. The landowner then gains exclusive access to his own land, which now becomes profitable for him to invest in, and transform into very productive arable land. Will the landowner work all this land by himself and eat all the produce? Obviously not. Some of the cottagers are hired locally, as farmers on the newly productive land that requires a workforce. Others move to the city, where the price and availability of food become much better as a result of the improvement. Whichever choice they take, they are no longer half-starved, and at least they have a chance to work for a better future. The alternative you seem to be proposing - dispossess the landowner, distribute the marshes among the cottagers - is not practicable, on account of the large amounts of capital needed for improvement, which only the landowner can reasonably obtain.
This being said, I think we agree on two points: the Enclosure Acts increased the pace of urbanization (but I believe it was by providing cheap food, not forced relocation), and they also increased the prosperity of society in aggregate. On my side, I argue that this prosperity registered a net gain for both landowners and the poor classes.
While acts of enclosure were an old custom in Britain by the time of the industrial revolution, the discussion here was about the effect of those acts at the time of the said industrial revolution, i.e. late 18th century. The last riot that your link mentions ("the Newton Rebellion was one of the last times that the peasantry of England and the gentry were in open armed conflict") happened in the early 17th century.
I was refuting your earlier points specifically about the enclosure acts themselves:
> The Enclosure Acts "kicked" very few people off the land ... previously starving peasants moved into the cities to become well-fed
Your description makes it sound like some peaceful transition, followed by massive prosperity, everyone happy and singing, but the reality is pretty far from that.
> The poor themselves decided en masse to move from village to city at the time, which seems to indicate the contrary.
You have the same mechanism at work today, in slums in India, South America and so on. The draw is the possibility of being better off and having more opportunity than you would in a rural area, but it doesn't always end up that way.
But we're getting off the point, which is that a free market doesn't give you "unprecedented human health and prosperity" - the best that you can argue is that it's one of the preconditions (but not the only one).