At high demand times, you have to be very rich indeed to outbid a full bus without even thinking about it. There aren't enough people who can do that.
But say this does happen a lot-this means rich people pay enormous road use fees, which can then be used for road maintenance, construction, and improvement, as well as other transit infrastructure!
So, the rich willingly subsidize infrastructure for everyone? Seems like a win-win!
That's a nice pipe dream, but what would happen in reality is that all of the congestion fees would go to the rich (perhaps in the form of tax cuts), who would use it to buy more stock, bribe some politicians to ban buses, and then triple the congestion charge because fuck you.
The congestion fees would go to the government responsible for the roads. Of course, they could be captured by the rich, but most governments spend most of their money not on the rich.
You'd set the congestion charge, by law (at least on public roads), to the minimum required for efficient road use- not the revenue maximizing price, which would likely be much higher due to monopoly.
Why do people insist on this tired unimaginative trope. We have the past and present to look at. We know how these things work.
The rules will be crafted, the commas in the laws placed, the contracts handed out, to support those who supported the endeavor. If the plumber's trade group agrees to support it their vans will be exempt. If Palantir supports it, the RFP will be written to make it nigh on impossible to not buy their stuff. No matter how flagrant the badness of the system, if the tech industry makes even a cent, the comment section full of techies will engage in olympic level mental gymnastics and not just do bending over backwards but doing full on backflips to justify the goodness of the system. If the bus drivers have such a comment section they'll do it too.
This is how things were. This is how they are. This is how they will be. Well, right up until the point where the rest of society gets sick of our shit and leaves us in a big communal hole or gives us a free shower or whatever happens to the fashionable way to do that thing is at that point in the future...
But I suppose maybe you're right and they'll throw a few pennies of tax cuts at it if they just need a little upper middle class support to drag it across the finish line.
And also in essentially any relevant private market for goods and services where capacity is limited, especially when there are more and less desirable times.