@glyph @markgritter @jalefkowit
All that, plus (1) no DOM access; applets had their own canvas and couldn’t meaningfully interact with the rest of the page (at least not until they were effectively dead), and (2) they required a separate plugin, not installed by default, so devs couldn’t count on them being available.
Though to Glyph’s point about startup time carrying the day: Flash had the same two shortcomings but made it much further by having a lighter footprint.