Usually what happens when things get regulated at the state level is that change is a lot slower to happen, and the state might have either indifference toward or opposing interest with the city. There's already kind of a Portland-vs-rest-of-Oregon dynamic, plus a Portland-vs-Clark-Washington-Clackamas-Counties dynamic.
I think the process that we've done in Portland is pretty decent: have a prototype/trial period, see how traffic patterns change, evaluate trade-offs and safety, then pass laws based on the experience. Lyft even previously worked directly with the city to develop and implement these local rules.
It's not clear to me that preventing Portland from regulating services like Lyft without state intervention is a win. Certainly Bend, Medford, Seaside, etc. would probably benefit from their own rules. Perhaps legislation that facilitates some basic ground rules would be helpful, but also allowing for additional local regulation would be the best fit.
When the state complicates or bans local regulation/development, seems like the trend is to just stop it and then do nothing else. For example North Carolina's HB1 bathroom bill, Chattanooga's municipal fiber vs. AT&T's lobbying for bans, Atlanta's MARTA being at the mercy of the state legislative branch for its funding.