I have such experiences as well, not in Bay Area, but in tech startup. I am quite sure that is not always the case (maybe even mostly not the case) but I've found that one of the autistic trait is to have difficulty with maintaining conversation, including difficulty with recognizing when is your turn to speak. There are even questions like that in ASD questionnaires freely available online.

The reason usually is that people gets really excited about what they want to say. So excited that it is difficult for them to hold on. Especially when they can guess where interlocutors are coming from and what are their points so the rest of the sentence seem obvious.

I couldn't find any compelling research or article but there is this notion that mild autism is more frequent in Bay Area. Not only there, in general, it goes in par with high concentration of engineering staff.

If that's the case, I think people may not even realize they are jumping in and it is not something that they can easily harness. Probably the best option would be to wait when they finish and then continue with what you wanted to say. You might signal politely that you're not finished yet. You may also arrange a short chat dedicated especially for this issue, as long as everyone keep calm and respectful I see no harm in it. The other option is to speak with your manager about it as (s)he's in the best position to speak to single member or an entire team.

I know it's a massive effort to harness jumping in, but it can be done in many cases.

(edit: just fixing pronouns)