Another factor is a wider use of all sorts of CMS (WordPress etc) for content presentation, combined with often slower/underpowered shared hosting and script heavy themes.
On some cheap hosters it may take a second just to startup the server instance, that's before any of the outgoing requests are done!
Yep - to the executives, saving a couple of (theoretical) hours of development work is worth paying a few extra seconds per page load. Of course, the customers hate it, but the customers can't go anywhere else, because the executives everywhere else are looking for ways to trade product quality for (imaginary) time to market.
On some cheap hosters it may take a second just to startup the server instance, that's before any of the outgoing requests are done!