Nice Bait.
To be honest, noone said that non-raiders shouldnt have Gear Progression, but in my opinion you are pretty new to MMORPGs. If you had experience over Years in the raiding Scene, otherwise you could answer the question in your last sentence by your own.
Why does People always wants to earn more Money? Because you never can have enough Money. Same goes for your kinky example about dicks. It is called Human nature. People always want MORE. Thats the reason why MMORPGs turned this way we have it now. Non-Raiders and Casual Gamers found this genre and enjoyed it, but they didnt wanted to spend so much time in a "Game" but they also payed their Monthly Subs. Sure every Company would do everything to earn Money. And all about losing Raiders and stuff is because of a break will remain as speculation by your side.
Themepark MMOs tend to have linear Gearprogression -> Ilevel over Ilevel over Ilevel, over and over and over. If it goes on Topic, i already said - Caps should be per Job and not Character. And with the "on the tight leash" i meant that 5ilevels are a joke for the time you have spend into the raid. All stays and falls with the rewards. Glamour/Mounts/Titels can be farmed later on, if the Content is old. Nerf happens, new max Level is added, etc.. etc..
Ill take another example for other situations: PvP, People did alot PvP to get their Rank up for the cool Looks, later on SE lifted the rank requirements for those PvP Sets, so everyone could buy that Items just for PvP Points w/o any ranks. Alot People flamed them for do so, same goes for the Anima Steps, reducing the Prices for the Anima weapons also isnt a healthy way for the Players they did the anima steps from the beginning.
So, i.e. i would absolutly follow your Point of View if the Mounts/Titel and Gear will be just obtainable aslong the Raid Content remains as relvant. Which means at the Moment when a new xpac Releases, there will be no rewards anymore for doin that raid, just an achievment for Clearing and the Storytelling.
And before you ask yourself, why do i see Things like this, for me it doesnt Count If i am the first one or last one who obtained Mount XYZ or Gear XYZ, aslong as These Items remain as "Rare" aslong as this Game exists.