There were more (non-indie) games being released at the time, thus having more good games releasing. The medium was also still developing, so titles were more experimental. Same for limitations in technology forcing creativity (and frankly nicer visuals, skilled pixel art and ~00's 3D have strong appeal).
Also what the other anon mentioned with the pandora's box of monetization. These days people even ask for monetization. Like damn bitch can't a game just release as a finished product