If you mean 'people used STR accessories instead of VIT accessories', then some people did use them at the cost of tankiness, yes. But not everyone did, and those who didn't were not getting kicked from parties, nor were they getting called out for their lower damage. In fact, I have a distinct memory of people complaining that people WERE chasing the damage, because it required using out-of-date accessories from the previous expansion, resulting in them being a lot squishier while progging a new fight (Susano and his TB)
If you mean 'people melded STR to accessories as tanks instead of VIT', that is because VIT on them was capped. Conversely, people would meld VIT to accessories as DPS to help survive raidwides. I remember seeing a meme where someone had opted to skip the VIT meld for more damage (by melding a Crit there instead). They were overkilled by the final raidwide spam of O12S by less than 100 damage, which the VIT Materia would have provided a couple of times over. Turns out blindly chasing 'more damage' might not be the best choice in every scenario, hmm?
I'm also not seeing where the 'hefty boost' (specifically in damage either for the player or the party as a whole) is coming from. Sure, you save the healers 2 GCDs each in P12S P2 by using the Esuna-Intervention effect as a PLD. Four total healer GCDs in a fight that is 8:45 (or whatever it is) long? What a gamebreaking 'hefty boost' to the group, around 1200-1300 total potency! One non Crit-DH Hyosho from your Ninja, and that whole 'gain' in RDPS is gone. Crit Variance will always, always, be a bigger impact on your damage than any system I could come up with, and unlike stuff I come up with, the damage swing caused by Crit Variance is already in the game, mangling the oh-so-precious 'job balance'