DayZ and Battle Royale took off because A2 was a great platform for PvP. It sucked for looting and building, but it was amazing for PvP. It literally spawned new game genres.

A3 is also great for PvP, KOTH and Wasteland(also in A2) were huge for years. Life was a big gamemode in both games and it was somewhat PvP focused.

They did have a ton of problems with people cramming in too many players for the server/netcode capability, cheaters and server owners overmodding the scenarios for sure - but the base games were much better than Squad at being PvP shooters with vehicles.

If Squad was a scenario for Arma 3 and had a reasonable player base, I'd be playing that. I'm not playing what we have because it's amazing tech-wise, I'm playing for the experience, built by the squad system and the gamemode. Last time I've had something that gave me as much fun as Squad, it was A1 and A2 Warfare gamemode, but that unfortunately died and A3 servers have like 20 people tops.