Is PUBG Following DOTA?
Disclaimer: I haven't played either of these games, I'm simply looking at stats that show their similar popularity trajectory, and the fact that they were both genre defining.
So I feel I'm already in trouble by saying that both DOTA and PUBG are genre defining, but I'm going to stand by that statement pretty solidly. DOTA created the MOBA archetype as a MOD for Warcraft III, and while PUBG didn't create the idea of a Battle Royale (I believe that title goes to the eponymous Battle Royale), it too modded an existing game (Arma) in a way that created an entirely new genre.
They both enjoyed explosive growth, popularity, and, since they'd created their respective genres, little to no competition. Then challengers came on in the form of League of Legends and Fortnite. Both of these titles introduced a much simpler and youthful look.
A lot of people will say the biggest factor of Fortnite's growth is that it was free. I think this would have helped its initial growth, since the fact of the matter is the battle royale mode wasn't even supposed to be the full game for Fortnite, but it now looks that the main game will never be finished. That said I truly believe that the biggest aspect of its growth was it's kid friendly look and feel.
Parents let their kids spend ridiculous amounts of money on mobile games, that's why that market exploded.
Free or not, Fortnite would have presented to a parent a less realistic, and therefore less violent, alternative to the game that was at the time far more popular (PUBG).
For League of Legends, it's look helped it break in to the Asian market, particularly Korea. It's sometimes hard to remember that Riot Games is actually based in the United States. This really was all started by World of Warcraft. Giving your game a more approachable look, that's fun and detailed, but friendly to the general masses (and in particular to younger crowds), really opens up your game to whole new audiences. WoW was able to take what was a popular, but niche market that was at the time cornered by Everquest and Asheron's Call, and give it universal appeal.
Now, DOTA was able to pull together a sequel, that doubled down on it's "hardcore" motif. DOTA 2 is in almost all ways more difficult than LoL by adding additional mechanics to track that aren't present in League. In this it has actually been quite successful.
Valve has been able to take this game and carve out a new market by pitting themselves directly against League of Legends. The battle cry now sung from DOTA fans is that their game is more serious, and LoL players are just too casual to play their game. Similar cries have come up from PUBG camps, but with rampant cheating issues, and their struggle to turn the game into an eSport, these cries have really been more sad wimpers than rallying call.
PUBG needs to figure out a way to tune itself in to that hardcore crowd again, make it the more serious alternative to Fortnite to pull it's fans back in. They shouldn't have to strive to mimic the aesthetic games like Fortnite thrive on.
Valve has proved that the best way to combat this is to embrace the hardcore nature of a game. Play it up, and create a sense of competition between the camps. They gave their fans a game that legitimately is more difficult than League, and whether or not that's your thing, it helped create a strong fan base that has kept DOTA 2 popular for a good long while now.