I've been using Infuse Pro to stream from Google Drive for a good while now. There a reasonably lengthy initial buffering period (much more than Netflix etc), but once it's playing it works fine. Infuse plays pretty much everything too and handles soft subtitles. It can even find subtitles for you online. Plus it finds metadata too, including cover art.
Basically, Infuse is great.
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Geeky? Took me about 30 seconds to set up Google Drive in Infuse. It's incredibly simple to do.
I agree that the ATV (same with Roku etc) are becoming less relevant though. Most people really only need two or three streaming apps, which they're almost certain to find on any modern TV.