Until the MSN messenger rebrand in 2005 sounds like a good rule of thumb.
HTML? FTP? People just want an online presence.
I think the point of no return was the launch of the iPhone. Not that the writing wasn't already on the wall, but everything accelerated after that, and it was clear things weren't going back after those devices took over.
My Uncle was a headmaster for about 35 years. When I presented a laptop to him, he couldn't use it. Told me he had never had to use a typewriter and couldn't use one. It was a really hard hurdle for him to adapt to a keyboard. And he still struggles.
The thing I'm really uneasy about is the Googles tracking everywhere you go, and all of that. It's very difficult to opt-out of tracking. I desperately tried to suppress my location from Google for years, and in one afternoon with a product activation via location/bluetooth they finally appeared to get it. Play services etc., make harvesting your contacts, reading your mail, and following you much easier. And it then becomes that bit easier to turn you into a commodity.
My Samsung was pre-loaded with Facebook. These are shitty little tricks. But advert networks in the browser also make it very difficult to escape the big trackers without a fight. Fingerprinting is everywhere.
We also dump files into the cloud these days. Which is very trusting.
But maybe the API was ultimately a trap. A la "Embrace, Extend, Extinguish". Offer an API to encourage adoption, and then start restricting it later.
Which got us to leave our federated platforms with open protocols and enter closed silos.
It's fair bemoan about the state of the web now - there's many faults, but it's considerably more accessible than it was before. There is more information available that's, and more opportunities for people on this new web, and its all (ultimately) easier to access