Since Wily bides his time until either Mega Man or his robot bunch du jour have offed one another, and robot masters always take over some place to turn into their fortress wouldn't Mega Man be able to practically stop Wily by just not bothering?

"Well, we're down a couple of factories, an airport, a bit of ocean and two acres of forest but if this works we'll have achieved world peace!"

Wily wonders from his fortress what's taking so long out there.

Meanwhile Mega Man has taken a nap.