Then again the LGV Est took a similar time per distance (took 12% longer but covers 25% more distance).

Then then again, the LGV est was largely in the “empty diagonal”…

Instead, we get the redundant Bart to San Jose (Amtrak has been continuously providing that route for a century or something.), and SF to SFO (caltrain covers that already).

They need to pick one rail technology and move the entire region to it, then dictate the legacy systems operate in a unified way (allowing regional, independent rail authorities to completely override city councils, sacramento and DC), with the understanding that they will be fired if the transition to a unified system takes more than 5-10 years.

Instead, they are doing the exact opposite of everything I just recommended, and all the systems are falling into disrepair.

For one thing, it would cut 15-30 minutes of travel time between Silicon Valley and SFO, and Silicon Valley and Oakland.

there are many, many problems with BART's SFO extension (courtesy of quentin kopp), redundancy is not one of them. there was no BART to caltrain connection prior to the SFO extension, and caltrain is a completely unserious transit agency running hour headways.

genuine problems with the transit system in the bay area abound, you should pick one of those to complain about instead of some weird fixation on incompatible gauges