Why on earth would you play if it's just a grind to you?
I can answer for myself, even though as an old school MMOs player that kind of grind is not really much for me, so can't say I did enjoy it, but can't say I did hate it either (given an option to get infinite free credits I'd do it, though).
I enjoy taking some odd (and different) cars for a drive on a few tracks I like.
Given the total lack of the promised "back to the roots" campaign and cafe being so short and lacking, the only way to do so now is custom races (Online too, I suppose. I don't enjoy online in GT, though). Custom races don't pay a thing, not enough even to upgrade/tune some cars.
So pretty much to enjoy what I actually like doing in GT7 I did grind my way up as well, just missing a month worth of LCD cars now with 100m saved (out of needed ~130m, but there's a 100m limit cap).
I do miss a few golds in circuit experiences here and there, some golds in the S tests too, but aside of that and waiting for the new content such relaxed and "custom" driving is all I care about in GT7. I do find it enjoyable experience as the actual driving GT7 got right (except the rally races). The rest... not so much, not yet at least.
If you like GT7 enough to actually play it enough/full time for another 4-6-12-more months, then good for you I suppose. With how I enjoy playing the game I'd never get to try/drive fun cars without the grinding. 1-1.5 hours a day of custom races is literally nothing credits wise. I still like it for the reasons I said above, too, but there are other games to play in my free time.