.
I often think that carbon or extra strength type boards are more suited to people who do break a lot of boards, so for them, a normal seven ply board might last one session or so, but having a carbon type board, at least it might last more than a few sessions for them, which at the end of the day is the main thing.
There are some guys I know who skate the same Powell Flight boards day after day, month after month, even re grip them when they need to, mainly because all they skate is mini ramp or bowl or vert and almost never actually drag the tail or pop their board, so the thing never wears out. The funny thing is those are the guys who could ride a normal board and still have it last a long time, but I guess they have the money so get whatever they want in that regard.
For everyone else though, any normal skateboarding usually means the tail (and often nose) will wear down so that determines the length of life of a board more than anything else, barring it ending up in two pieces or broken from whatever bad landings, etc.
If keeping things stiff and not getting flexed out is key, then I could see those other type of boards working well for someone, regardless of how long they actually last for the person, but the bottom line is how much are people wanting to pay compared to how long the thing will last.
People can make up their own minds there really.