I find the dynamics of lichess.org vs chess.com very interesting.
They are similar in terms of features. Both have decent interfaces, puzzles, matchmaking, live viewing boards and broadcasts for tournaments, training programs, etc. But chess.com has ads, and features locked behind subscription paywalls where lichess.org does not. (Everything is free on lichess, except for the little logo next to a user's name to say they have supported the site with donations.)
But on the other hand, chess.com seems to have a higher number pro players; and probably a larger number of players overall.
I think its very interesting to think about why that is the case. Why would more people choose the version that is more expensive, but does not have more features?
I've thought of a few reasons, but I think probably the biggest effect is that chess.com has more money to splash around (because it sells ads, and asks for user subscriptions), and it uses big chunk of this money to advertise itself. eg. by sponsoring players and streamers, offering larger prizes for its own tournaments; etc.
And although I definitely think lichess is better, since it is generously supplying a high-quality product without trying to self-enrich, I do sometimes think maybe what chess.com is doing is ok too: in the sense that it is not only self-enriching, but also supporting the sport itself a bit by paying money to players, events, and commentators. Lichess does this too - but less of it, because they have less money.
(Note that chess.com also does some really crappy stuff, such as censoring any mention of lichess in the chat of their twitch broadcasts. That definitely does not help support the sport.)