Yes exactly. I would also debate the popularity point: how many games released by 2003 (release year of The Frozen Throne) still have an active pro scene, meaning people whose job is to play this game at tournaments?
With the rise of streaming I'd venture that most pro players do not rely solely on tournaments (and their tournament sponsoring) anymore, but the point remains that the game seems to have seen an increase in popularity in the past few years.
The Warcraft 3 scene is nothing compared to the biggest names in esport, but it is still remarkably healthy. One reason for this is that Blizzard let the community take the lead unofficially with things like https://www.w3champions.com/ which is basically like Battle.net but better than Battle.net has ever been in many regards.
I think it also helps that WC3, as a RTS, can still be relatively enjoyable as a beginner: fewer units to control, fewer resources and buildings to manage, and at the very beginning (say, with 50 APM) focusing mostly on the first hero (meaning a single unit) is clearly the best return on investment to increase one's win rate, which can become apparent after just a few games. Few RTS games are able to both offer such a gentle learning curve and the depth required for people having played the game for more than 17 years to still refine their strategies.