It's less 'pay to win' and more 'pay to catch up so you can go into a static'. T9 requires a serious, skilled group, and putting together one of those who are willing to commit to a raid schedule when 90% of serious, skilled groups are trying to down T13 is a pipe dream. It's 2.2 T5 all over again, basically.

The other option is suffering through DF so you can suffer through PF - if your server is even willing to join a progress/learn group. It's a process that can take weeks to months depending on your luck, at which point you're gonna have to buy your FCOB wins to join the only FCOB groups that fill.

But why do any of that when you can just craft/convert/marriage band up 5 million gil and purchase a run? Well, maybe you're one of the few who wants to actually attempt to execute the content, but you're a stark minority on most servers - so get used to AFKing in PF while you pray a straggler static picks you up and actually stays cohesive in the process.

It's not really the sellers' fault, though they're economically motivated to lobby for the status quo. It's the shoddy loot and raid progression design FFXIV's endgame is plagued with.