You might be a little low there. In my direct experience as a driver pre-covid, it was close to 50%, and many drivers in the relevant subreddits have reported it frequently being more than that since. Imagine hearing a passenger complain about their $15 fare when you only see $6 of it (out of which you still have to cover your gas usage). 25-30 percent seems reasonable in comparison.
This type of cut, plus the massive false advertising that Uber/Lyft does via their apps in smaller towns, like telling you that your ride will be booked soon when there are literally no drivers available, have led to me just using prebooked car services when I can now. It costs a bit more, but they are 100% reliable in my experiences, more money is going directly to the drivers, and it supports the local economy.
I got burned on this using Lyft to get the airport early in the morning. Scheduled the night before to pick up at 5am the next morning. No one was actually scheduled, and it was just searching endlessly for a driver in the area but there were none! No car services open, I had to call my mother and ask her to take us! I couldn't believe it and I'll never use one again. Only car services for me now, at least for anything that matters.
Uber and Lyft are (gig economy) cab companies.
My last ride I was talking to the driver about someone canceling a $50 fare and her getting it instead which lead to the discovery of her getting $22 of the $48 (minus tip) I was charged.
It amazes me people are still driving for them.
I talked with some ex-cabbie Uber drivers. With cabs, they had to pay back the owner each shift for use of the vehicle and license. About half of the shift would be worked free. If they were new and got weekday graveyard, it was particularly bad. They seemed much happier with Uber. I'm a bit concerned about hard to quantify costs like vehicle wear ultimately making it worse, though.