They mentioned 1000 tabs which may go some way towards explaining it. If that's not how you're supposed to use Chrome (I'd understand if it wasn't) then I'd imagine some kind of notification to the user would be helpful. Something like: "Chrome may be a little slow, you have 1000 tabs open" including perhaps a table suggesting tabs that could be closed (i.e. if she's opened https://bbc.co.uk/news in 20 different tabs that were last accessed a month ago) and an easy mechanism to quickly do so.

I actually know of quite a few people who use browsers this way, so it may not be a terrible idea to have something like this.

The computer is fine, judging by Firefox starting resonably fast with very many tabs to restore for her on that computer.

Also the same chrome profile starts very fast when she uses the "private browsing mode" which doesn't restore any tabs. So it really just seems like chrome having perf issues with tab restore with many tabs.

Maybe it’s extensions.

But anyway the point still stands: an outlier user with 1000 tabs open had a slow startup time doesn’t mean Chrome is horribly engineered. If it isn’t an extensions issue then it’s a minor bug.