I've seen a lot of those highway projects. For practical purposes, a $billion is basically table stakes - you need that to be credible when proposing anything of substance. Same with transit projects. It's still slightly less expensive per mile to build regular railroad improvements, but those generally don't have the passenger capacity of transit running at least every 15 minutes.

Yes, rejecting the offer of the Coast Line was definitely the biggest failure of the Pete Wilson era. But really, he was never into a lot of highways either; I was there at the time. He just didn't want to spend money. I think the only reason he went along with the Trolley was because they figured out how to do a minimally viable project without federal funding. The extensions and reconstruction projects have cost a lot more per mile, even when still on the old railroad r/w (e.g. El Cajon).

I used the Sacramento RT light rail once last month. It ran mostly on time, though still every 15 minutes, and was reasonably clean. Security was noticeably absent, compared to what they had pre-Covid, but the crowd (outside commute time) was fairly small (could easily have fit in a bus, per car anyway). Since they've never had more service than that, in relative terms, they probably fit 2 of your 3 criteria - more security would be nice, even rent-a-guards who could call the cops if needed.