I read the beginning of the post and immediately tabbed back to start writing a rant about standing up a website being fine, but the real loss of web functionality was Flash, glad I kept reading. I'm quite good with CSS and doing tricks with SVGs, but constantly run into things I want to do in 2D web I find to be complex enough and time consuming enough I don't even bother, while I would have been able to do it in Flash as a 13 year old in a few minutes. The modern web is a prison built out of <div>s, the tricks you see for "amazing" websites with obnoxious scrolljacking/parallax don't hide it.