Sometimes it isn't that simple.
First off I'm going to assume this hypothetical person HASN'T been playing for 2 patches, but is 2 TIERS WORTH OF CONTENT, meaning this person is on BCOB while their friends are on FCOB. Tiers, not patches. Also, this person has NOT been playing for six months.
Let's say you have 3 friends that play the game regularly. Which is pretty normal. It takes time to build a large group of friends, and having a few is pretty normal.
Now, let's say again, that YOU are the only tank in the group. So, you and your friends get together to try to get your clear for t5.
Typically you either have to get your friends to call in every favor they have to get the group going, or you have to take a risk of getting bad players. Moreover, you, as the new player AND the tank, will screw up. This is inevitable, and perfectly normal.
For a new player.
Not for the "regulars."
So with each inevitable wipe, you risk losing a party member. You will always have a 4 person party, but you'll also have to deal with a possible revolving door of people trying to accomplish the same thing. Sure they'll hopefully clear it in 6 months, but being stuck on this content is extremely disheartening, especially once you get good enough and can definitively say it's NOT your fault.
And this is only t5. t9 is a completely different animal. This is also not considering that you COULD have 12 different friends or more, but without the right roles you're just not gonna be able to do it. If you have 100 friends but not one is a healer, and you're a tank, then you're STILL taking a risk. This is a hyperbolic situation but I hope I'm getting across my point.
I don't think people really understand how difficult it can be for new players to progress through content simply to get caught up. The game gets nerfed and made easier not for the people who are caught up, but for these people who are trying to get caught up in a reasonable amount of time.
Isn't someone who started after the gravy train by definition a newer player leveling their first character?
I'm not talking about people who have been dawdling on it since Ramuh was new content. I'm talking about people who, at this point, don't know the game without FCOB being in existence.