There is nothing wrong about needed appropriate incremental, like grade separation projects on the LACMTA light rail lines, in particular the Long Beach route.

Alternately there is a relatively recent precedent for a large scale all-new transit project and that is BART. Curiously what incremental BART has done subsequently is poor - extending a bastardized NYC subway ever farther into the boonies at great cost.

And PBCAHSR indeed has turned out to be incremental itself; it is just that the initial increment was intentionally located in the poorest venue in the hope of bowling over any opposition. How'd that go? The first increment should have been LA to Bakersfield via Tejon - a guaranteed successful proof of concept.