That was never the case.
Just that some indie that made "good enough" or "great" game got lucky that they got picked by "right" streamer or youtuber that liked it and it got virally popular off it.
Like I doubt Minecraft would explode as it did if Yogscast didn't pick it up and made a popular YT series about it, which also made modders jump on the then-barren game, making it even more interesting.
Pretty sure before Yogscast there was already the rollercoaster minecart video released and on Kotaku (and other sites) that made Notch a millionaire overnight.
Yogscast may have helped shoot it into the moon, but Notch had already joined the mile high club by then.
It may be a matter of marketing and luck to make money on a "good" game, but a brilliant game is destined to spread like wildfire, because the gaming community is enthusiastic enough to look for such gems and announce the findings.
Making games break even always was 90% marketing though, maybe the current indie scene had it's own little "happy time" period where it was enough to create a high quality game and put it up on Steam to sell on its own, but that definitely wasn't the case for "non-indie" games since at least the late 90's (the way how game marketing is done has changed dramatically though).