You're saying people should take a long time to rank up? Meanwhile people are almost lvl 200 running around with tanks, miniguns and RPGs, with millions of dollars, with no possibility for the rest of us to catch up.
I know what a long term MMO looks like, I've played WoW consistently since 2004, and there's always something good to do for progressing your character. If people ever exploited something (since as gold duping or chinese gold farmers), Blizzard would not just patch it but also fix the game to discourage the need to do that and encourage something better. In this case, R* has patched it but instead of fixing the problem they toss some scraps your way and offer you some micro transactions for your real dollars.
Nobody wants to grind missions or rig races, of course it's not fun, but there's no other good method to get XP and money. R* took away the mission replays cause people were making too much money, not because they were making good XP. Because that gets in the way of the micro transaction business. Yet we don't hear what their plans are to improve the progression experience.
Now I'm only looking forward to heists whenever they add them, hopefully they have good payouts & XP.