There's a difference between useful, and even very useful, and absolutely necessary. Clearly value types weren't absolutely necessary, as Java did well without them (and JS still does).
Gosling said that his goal was to have nothing you can somehow live without (I don't know how well early Java lived up that ideal, but that was the ideal). Hardware changes made user-defined value types absolutely necessary for workloads Java wants to target.
Being there since the beginning, I wrote my first Java game in 1996, early Java only did well thanks to Sun's marketing weight and it being free beer vs the alternative of having to pay for a compiler like Delphi.
I was around, too, and I don't think that was at all the full story. Marketing has never been solely responsible for the long-term success of any product. There were other languages that were very heavily marketed: VB and C++ (and FoxPro, too, I think) by Microsoft, Delphi, and about a million other RAD tools. Being free was one of the reasons, but so was targeting the web, and Gosling's design of wrapping a JVM that gave people what they wanted (dynamic linking, fast compilation, garbage collection) wrapped in a language that felt familiar and non-threatening. I don't remember what were Delphi's issues, but a big project I wasn't involved with at the same organization I was working at circa 2002 (I was all C++ back then) did Java on the server and Delphi on the client. Maybe Delphi didn't have a good server-side story?
