I wouldn't consider this post any big party-pooper. I was expecting a rant on a rifle that crapped the bed, and S&W wouldn't stand by it, or something like that.
I think the OP is making a fair point, and one that applies across the spectrum, not just to M&P Sports.
Gun owners largely DO seem to have this irrational obsession with goobering up their toys with expensive, often un-neccessary extras, often defeating the purpose of the budget weapon they bought in the first place.
But, that being said, there are degrees of upgrades, and not all of them are over-the-top, complete overhauls.
Personally I think these rifles benefit heavily from replacing that rinky,abrasive, all-plastic handguard with a Magpul guard.
They're vastly more comfortable and ergonomic, provide greater surface area for the supporting hand, and are heat shielded. And, they ain't real expensive.
Also, the rifle benefits from one of those rubber Tapco slip-on buttplate covers. Obviously recoil isn't an issue, but these little rubber Tapco units add more surface area to the stock buttplate, rounding out the uncomfortable corners, and shouldering much more comfortable and effectively.
They're solidly constructed, stay on very well,and for the mere $10 they cost, they're a very worthy upgrade for these plastic M4 type stocks, IMO. Try one and I'm sure you'll agree.
Other than these, I think the rifle is exccellent, as is, and the OP is correct: if you feel gotta change out half the rifle, you shoulda just bought a higher-end gun.