I kind of hope so. While they were very convenient, they had some limitations, and had some very confusing failure modes (for example, trying to go to an HTTPS site before accepting the boilerplate TOS agreements).
I think developing some sort of proxy discovery protocol and making it clear to users that their connection is proxied is a much better way forward.
Proxies are not the only thing that is necessary to support - login portals is another related usage in the same general area.
Basically the problem is that the encryption possibilities available assume Internet is a dumb pipe between source and destination, but that is simply not the case.
I think developing some sort of proxy discovery protocol and making it clear to users that their connection is proxied is a much better way forward.