WHY in the name of all that might be Holy, would an ISP not support Eudora and other such well known and decent email programs?

Why & HOW can they deal only with Outlook & Netscape? I suppose I am lucky to have choices in an urbam center, but I'd have a WEB-based email only before I'd put up with that sort of narrowness!

[I thought that any program that followed certain protocols(IMAP...etc..) would work with almost any ISP!..strange!]