It's not robust for saving things like private chats, or anything else you need to be logged in to see. If I read your page correctly you'd need to do each of those manually.

There are always edge-cases. A simple version of my solution can be coded up and fully implemented in an hour or less by a normal programmer (the hardest part is writing the SQL line for pulling out URLs from Firefox); the full version (a bot or daemon) could probably be done in only a few hours more.

Your desired solution, on the other hand, requires intimate familiarity with browser extensions and internals (if you want to save dynamic content and fancy things like Javascript-based chats, so much for trying to leverage existing solutions like the Mozilla Archive Format extension!).

Pareto.

Did you know the Internet Archive will delete based on a request by the website?

My understanding is that in all cases, these deletions are really more 'marking private', and if it's done via robots.txt, well, one day that robots.txt may be gone.

Some of the sites are also deleting posts fast, which makes it hard to archive on a schedule.

Note the on-demand archiving services used by my archive bot, discussed in my page...

For timestamping, doesn't the TCP protocol have timestamps in it, or are those not signed or something?

I'm not sure. It's possible that the packets have timestamps, but the encrypted content does not, in which case you don't get provable timestamping: the HTTPS encryption can be verified, but one could have modified the packets to read any timestamps one pleases because they're 'around' the encryption, not 'in' it. If it does, then maybe you don't need explicit trusted timestamping, but if it doesn't (or you want to work with any other data sources which don't luckily have timestamps built in just right) then the Bitcoin solution would work.

Also, many pages have timestamps embedded in them.

Now who's satisficing.

If there was a program that functioned like I wanted it to, would you prefer it over your solution?

I would consider it, but I would be somewhat reluctant to switch because I wouldn't trust the tool to not break horribly at some point.