I was working on my Private Pilot license in the mid-90's. I quit just around 40 hours with my only remaining required training maneuver being a Night cross country.
I quit for pretty much the reasons you give: while I could have afforded to finish my license, I realized owning my own airplane would have been prohibitive. Sure, I could get a Cessna 152 for around $20k at the time, but then hangar fees, maintenance, insurance, etc. were far more than I could afford.
There's a reason the average small plane owners at my airport drove Toyota rustbuckets with the bumper sticker "My other car is an airplane."
The cost difference between new and used is truly immense.
A new Cessna 172 starts at around $400,000, and that's before you start checking off things on the options list.
Used can be as low as $20,000 for examples for the 1960s. If you thought depreciation on luxury cars was bad...
The GA system is already frankly dieing due to ever increasing costs. Your suggestion would just kill it for good.