This isn't so true these days. Some websites are applications. That said, I think we need to leave behind the notion that all websites need to be applications, which seems to be a long-running trend.
2023 (224 points, 116 comments) https://news.ycombinator.com/item?id=35783189
2018 (730 points, 313 comments) https://news.ycombinator.com/item?id=17478133