It driven by consumer needs Michael, Now people are used to roaming the
world on their computers and the younger, well and some oldies, want to
play the video content of web sites, web builders use more and more
powerful so the builder use Adobe, Java, Flash and media players of all
sorts,,OSs have to then provided the platform and programs for us to run
these things.

Take the introduction of the BBC iPlayer. So many people had plagued the
BBC for past program viewing on their web site that they first
introduced streaming clips but people wanted who programs and even
program series to view because they had missed their favorite viewing,
so the BBC decided to develop a system that would do the lot.

... the Trust noted the strong public demand for the service to be
available on a variety of operating systems. The BBC Trust made it a
condition of approval for the BBC's on-demand services that the iPlayer
is available to users of a range of operating systems, and has given a
commitment that it will ensure that the BBC meets this demand as soon as
possible. They will measure the BBC's progress on this every six months
and publish the findings.

Even the browser builders had to try to keep up so the BBC promised to
help them.