Everyone willing to be a mindless cash cow spending anything on those skill lines, shouldn't have issues buying skyshard packs aswell.
ZoS really needs the money. Multi million dollar company with already big profits, being lazy not fixing actual bugs, but rather keep milking their brainless cows, they need cow support!
It's not like they are greedy and prefer blatant cash grab over a good game these days.
So yea, go buy skyshards, so the upper floor can pocket more money that won't help the game.
You can still do those quests and still gain the skill points. You just don't have to do the reputation grind if you don't want to.
If ZOS gave you those skill points, they'd either have to take away those quest reward skill points for players who bought them, or you are begging for double skill points.
They can't do that, because if people bought the skill line, then later did the quests, they'd get double skill points. Maybe they can code it so they won't get double skill points, but it seems like it would be a difficult thing to do that they wouldn't think was worth their time.