IPFS is a very exciting technology, but I fail to see how it could completely replace HTTP.
How could you make REST APIs with IPFS for instance? You’d have to generate a content ID (CID) of something dynamic. Every time a webapp requires a server-side logic like for templating or a centralized database, HTTP is still necessary, unless every peer on the network runs the webserver and has exactly the same database (which would be a very big security breach, let alone the fact that no one would want to host your webserver on their computer).
I agree that if all your website is static HTML pages, images or videos, it could very well be served with IPFS though.
Thank you for your help.