The biggest thing you're ignoring is that Prop 22 brings real, tangible benefits to workers compared to what they have today. It has companies pay I believe 41% of their healthcare costs, whereas previously this was 0%. And it includes the 120% of minimum wage provision, on top of vehicle maintenance costs. This is real money that real drivers and couriers will be "topped up" in certain cases, that they simply weren't being paid before.
The choices were 1. the previous system where drivers were purely contractors, 2. the AB5 world where the vast majority of them can't work at all anymore but the ones that remain are full-time employees, without the flexibility that attracted many of them to this work in the first place as opposed to, say, getting a job at a traditional taxi company, or 3. a compromise where the work stays fundamentally the same but pays more in many cases.
Most of the people I saw opposing prop 22, which I'm guessing includes the above commenter, and certainly included the legislator behind AB5, were just bystanders who viewed it as yet another a philosophical showdown of unionized full-time work vs anything goes exploitation. Even though that framework is a poor fit for the details of this particular situation.
The people with skin in the game saw it differently, the details actually mattered to them and they voted accordingly.
> overturning its provisions needs a 7/8 majority in the state legislature.
Given that prop 22 overturns a law that had recently been passed by the current sitting legislature, there wouldn't have been any point to doing it if it could just be immediately repealed by the same people. Prop 22 can be still be overturned with just a >50% vote by a future ballot proposition.