You are making stuff up, though. Either that or you're just selectively quoting "reported" figures that suit your argument best while ignoring all of the other "reported" figures that don't.
His salary has been estimated to be anywhere between £200k and £300k since he signed for us. The agent fees have been reported as being anything between £10m and £35m.
You've also waited until now to say that it's 4 goals and 3 assists in the Premier League, rather than his overall total, which is what you implied in your original post. Sneaky.
He's also not been here 18 months. We signed him in August 2021. That was 14 months ago. He won't hit 18 months until February, at which point he'll be another 20 games (roughly) into his time here.
Anyway, do I want more G/A contributions from him? Absolutely. But I'd expect more than 10 G/A contributions from any of our attacking players, regardless of what they cost.
But I've never argued the opposite and I've never said that goals and assist don't matter. What I have argued is that Grealish mostly makes up for his shortcomings in other areas of his game.
He's been a good signing. A great signing? No. But he's been solid. Could he bring a bit more? Yes. Has he brought enough to the table as a team player? Yes. He's been a 7/10 player thus far.
We didn't pay £100m for Grealish because we thought he'd be the best player in our history, we paid £100m to Villa because we wanted him in our squad and that's what they charged us.
If you'd told me in August 2021 that he'd have 10 G/A contributions by this point, I'd be a little disappointed because, as I said, I just expect better numbers from our forward players.
But if you'd told me that, at the same time, we'd win the Premier League with 93 points while Grealish started the majority of games, topping the league by the end of October 2022, I'd be just fine.
In fact, I'd be curious to look out for other areas of his game where he improved the rest of the team.