JVM ran in relatively little memory back in the day. I remember running applets on ~16 megabyte systems. Compare that to today where you need a half gig of RAM to even launch a browser.
Right, the internet caffee computers I used to hang out at in the early 2000's had around the 128-256mb of RAM memory, and Java/Flash used to run just fine. Although Java Applets usually seemed to take longer to download, and used to wait a lot of time to start the JVM after that.