I've thought that, buy another for spare parts and you're still ahead, and have even said it sometimes. But when you get down to it, if I had a Kent Road Bike I wouldn't really want the same parts on it. Why would you not want a Claris Derailleur replacing whatever is on it now? Or even Tourney, they work well enough.

If I was thinking of riding that bike, or a similar bike, for potentially thousands of miles I wouldn't think twice about an inexpensive wheelset. If it's lighter, stays true, the axle doesn't bend and it has a hub that I don't have to grease after riding through water puddles, is it really that important that the wheels cost more than the bike? I just disagree with the perspective that it's not well spent - in my opinion it improves the bike more, for less money, than a new wheelset on a mid-range bike would.

I wouldn't put aero carbon wheels on it but a $20 bottom bracket, sure! Or splurge $30 Sora brakes; they're exactly as useful on that bike as on any other. Just know that there are limits to what you can reasonably expect from a $129 bike.