I do think Texas's plan is one of the most promising, but I suppose my guess is that it'll still take a long time, partly because it's been looking promising for a
long time now: the first feasibility study was launched in the 1980s. The state actually awarded a contract to a private group to build high-speed rail in the Dallas-San Antonio-Houston triangle, under terms like those you discuss, in 1991, but it was killed, largely by Southwest Airlines lobbying, in 1994. I went to high school in Texas 1996-2000, and a new high-speed rail plan was being discussed that entire time too, but the talk never went anywhere. In the early 2000s, it was revived once more, this time as part of an ambitious Trans-Texas Corridor (which would have had freight rail, high-speed rail, car-only freeways, and truck-only freeways), but that died a few years later as well, partly due to a nativist backlash against its role as the "NAFTA superhighway".
Now there's yet another HSR plan, separated back out from the road plans, which might work this time, but I probably wouldn't put any money on this being the year the 20+-year impasse is broken. Honestly I haven't seen any of that supposedly lighter-touch, actually-functioning Texas state government on this issue, just a multi-decade series of special interests and politicking resulting in no rails being built.