Since the Adobe Flash Player will soon expire next year, what would happen to the websites that still uses it?

So what would happen to the websites that still uses adobe flash player, especially the old and abandoned sites that are made more than 10+ years ago?

From time to time, I know I have come across some websites that still uses Flash, and as Firefox and Chrome users may already know for instance, there has been some announcements about its future termination by the end of next December 2020. The Internet Archive also saved some websites and webpages that uses Flash. What would happen to the access of those kinds of information once Flash closes down?