The early build quality was poor and they had a lot of problems with ordinary things breaking that had nothing to do with being electric and everything to do with being inexperienced at making cars. They could be doing better now but it's a little early to say because the more recent cars aren't that old yet. Either way it seems more like teething issues than something they won't get right eventually.

Meanwhile it's fairly unambiguously true that electric drivetrains are a lot simpler and should require less maintenance in general.