You are either refusing to address the central point or your reading comprehension needs a lot of work. A premise of your original post was that libraries have newer devices than some users. I maintain that libraries should not have to be a fallback for your crappy website.
Right, and I’m positing that you don’t need to support 20 year old devices that receive zero updates because everyone has access to libraries in an absolute last resort.
There are limited resources when developing software. This is a pretty bad resource sink.
There are types of software for which I’d largely agree with you. Websites are not one of them: it takes effort or incompetence to make them slow and inaccessible.
My point is that websites are particularly amenable to being cheaply built in a fast and accessible way. I would say classes of, say, macOS apps are similar. Government certainly should be insulated from at least the market pressures that push websites into being slow and inaccessible. Competence is more a roll of the dice, I’ll grant you, but I’m not as pessimistic as you on that.
If we were talking about JS or Python or something, I’d agree with you. Most people just don’t have expert-tier knowledge of pure HTML, and even if they do, they’re slower to develop. I could get a feature out today to 99.9% of my desperate users, or I could get it out to 99.99% by waiting another two weeks. It just makes no sense. It has nothing to do with pessimism and everything to do with economics.