Do you have any evidence for that?

Kicking people off for accepting rides and then canceling them makes perfect sense because once you accept the ride, the customer is waiting and they're not looking for another driver. It also discourages drivers from looking at the destination and then refusing rides that legally they're not supposed to, like trips into black neighborhoods.

Accepting in the first place either happens or doesn't in only a few seconds, and if you don't they immediately go on to the next driver. At best they have the incentive to make you manually re-enable your availability to drive if you neither accept nor decline more than a couple of rides in a row, so they can stop routing rides to you if you're not actually there. In makes no sense to kick you off over it, so why would they do that?

Because the added delay for customers is bad UX, and so is the increased price customers face when there are fewer drivers willing to accept rides.

Only anecdotal. I have an Uber driver friend, and other drivers have told me the same. I live in a very suburban area that's basically shut down for the winter season. There is often only one driver even active within 10 miles. It's not a problem in a city.

Getting switched offline after too much inactivity, from which you need to actively affirm intent to work by going online again, is not the same as getting kicked off the platform.