The "grind" they keep whining about is actually pretty fricking light compared to... I dunno... anything that vaguely resebled an actual grind? A game like this requires advancement. It's what keeps people coming back.
"Gotta get this mech leveled."
"Oh, I really want that new mech that's coming out, better scrape up the space bucks!"
Without advancement, there's no incentive. Without incentive, people stop playing. Without people playing, there's no new players. Wither no one playing and no new players, there's no money. With no money, game goes bye-bye. If you speed advancement up too much, it goes so fast there's no feeling of accomplishment, and it might as well not have been there. I'm sure some people will try to deny it, but even subscription games have some kind of grind, because they HAVE to provide a way for people to generate that feeling of accomplishment, so they stay interested.
Does it apply to everyone? Hell no. There are also the spoiled brats that never feel like they should have to put forth any effort to get whatever they want. But those people sure as hell aren't going to keep PGI in business. If they were, they would have already activated premium time, bought Hero mechs, and would be making space bucks hand over fist instead of whining about how long it takes them to get {Scrap} for free.
Now, I'm not saying it's the best system ever done, but it's certainly not the worst, or even on the bad side of average.
And the "not everyone has all that free time" argument is total {Scrap}. If it's gonna take someone X games to buy a mech/weapon/module/whatever, then it doesn't matter if it's X games over the course of a weekend, week, month, or even year. They're still putting in the same amount of play time. What the hell do they need new {Scrap} for, if they've barely had a chance to play the old {Scrap}?