Now this is interesting. I've seen a lot of "40ties", "90ies", etc around, and I'm not sure why people do that. But once you've done it, it's clear how to read the text. Most of the non-numeric suffix is redundant; people mean "forties", not "forty-ties".

But "2000ies" has no potential redundancy and no plausible pronunciation. It's spelled as if you're supposed to pronounce it "two thousandies", but there's no such thing as a thousandy.