Isn't this the reason for HSR?
I was watching a HSR video for FL. It would go Jax > Orlando > Miami (and would make sense to go to Tampa).
There would be 2 lines - one that stops at the bigger cities in-between and one that only hits the 3 big hubs.
If I was living in Jax and could get down to Miami in 2 hours, I'd do it all the time. That drive sucks and it's stupid to fly. I imagine it would be similar for LA > San Diego or other close urban areas.....stops for all the 200,000 people ciites and stops for only the big hubs.
Our existing passenger train system is embarrassing. But hey, HSR may just be a case of keeping up with the Joneses.
Remember that it's not always that easy.
To make it HSR, you really HAVE to eliminate the stops. Which means that you're optimizing for LA--perhaps Union Station--to the San Diego city center.
That's great, if you either live really close to Union Station or San Diego city center and your ideal stop is exactly the other city center.
Of course, that's not very common. The LA/OC/SD megalopolis is one giant experiment in sprawl.
So... Let's say you want to go from LA to SD. First thing you need to do is figure out how to get to Union Station. Driving there might be possible, but then you need to figure out parking [and pay for it] for the duration of your trip. Uber/Lyft might be possible, but depending on how far you might be from Union Station, might not be particularly affordable. If you're in the general vicinity of a Metrolink station, you can take that to Union Station, but you might be backtracking or going out of your way just to get to "high speed" rail.
Then once you get to San Diego city center, you ask yourself--where am I *actually* going? If your destination is downtown SD, that's great. But because SD county itself is a gigantic sprawl, it might not be.
There's a better way...
Amtrak already has the Pacific Surfliner line. LA->San Diego is about 3 hours, which quite frankly is a little longer than the traffic-free route, but it's rarely traffic-free, so really not that far. But it has 10 stops along the way, which makes it MUCH more convenient for the people getting off and getting on. You pay a price in time, but for ridership, the added convenience of additional stops is a big thing.
It shares tracks with Metrolink (which covers LA/OC and goes as far as Oceanside) which has more stops, so it's a lot more convenient if you live REALLY close to one Metrolink stop to ride that down to Oceanside and then hop on the Surfliner, or from wherever you live to Union Station and then hop on the Surfliner. Likewise SD County has their own rail system--which I'm not very familiar with, but which shares several stops with the Surfliner.
----
You see this is the problem with HSR. If it's truly high speed, it only makes sense point-to-point, which makes it very impractical for anyone who doesn't have the same origin and destination. If you force it to have stops, it's a lot more useful, but no longer high speed...