I would say that the responsibility on the developer for that vision to occur is to write standards compliant code. Working around bugs or quirks in a specific browser I think falls into the realm of business case.
"Works in WebKit" isn't necessarily equated to "write standards compliant code". For organisations that manage to develop a website that requires a $100,000 outlay to work in Internet Explorer, that can't possibly be a web standards compliant code base they are starting from.
