They haven't. If anything, they've gone the other direction and balanced it around the 99%. Go look at how we have the 2m Meta which is stale, the jobs being homogenized.
Both. They both pay the bills. It's still a sub at the end of the day.
Irrelevant to your argument.
It never hurts to try something different. I haven't stayed in one job the entire time. I play with other jobs to get a better understanding of the game(if not to have a fresh gameplay perspective). Being stuck in one area gets stale in any video game so you know.
You're essentially noting the equivalent of a monkey only pressing two buttons on a gamepad. Sadly, this is the state Healers are in when there is nothing to heal - and I'm not talking about miniscule amounts of damage the tank is taking that Sylphies are healing constantly. I'm talking about big damage to everyone and Tank Busters. If a Healer only has 2 Buttons for their damage? It becomes very stale. Yawntrail did nothing for that and gave Healers a bone with no food on it.
This is where homogenization is a problem. If all the jobs feel the same, 2m Burst Window, feeling of rotation, etc.? It doesn't matter what job you play. You're just playing the role. What people want is distinct jobs that actually play differently from each other, and if they happen to be harder? Then you can decide whether you want to put in the time to play that job or learn a different job. There are still nuances that are unique to the job, but it's not enough to sate the player palate without it being talked about as the 'forced equivalent of X Gauge Management or Y Job' nowadays.
BLM already is getting QoL, but is also getting some hefty buffs that upend its identity. WHM plays relatively plain and simple. We can even talk about SMN vs. RDM/PCT/BLM. SMN is a braindead job because of the fact you only have to play with crayons and get the Blue, Orange, or White Crayon every 60s. It's super simple, and is lacking nuance compared to previous SMN, meanwhile these other Casters have some work that needs to be put in to get them to work. There's nothing wrong with an "easy job", but it's a matter of if people are willing to put in the time and effort to learn the job.