I assure you that 20 years ago websites with chats existed and they worked fine. Which means they weren't so huge because it would have taken days to download that amount of stuff.
The things developers usually forget is that there are other stakeholders than the computer executing code - IMHO a lot of developers would benefit from developing a bit of business acumen.
This is exactly the type of business acumen that is missing.
This is exactly why developers need more business acumen.