Like I said, If you're getting the right sounds, why would it matter how you get them?
Lemmy, like all metal musicians are aiming for a sound which you may not consider quality but many others do. I think Lemmy's bass lines were often pretty much perfect for Motorhead's punk/metal crossover sound so where's the lack of quality?
As for not being influential. Motorhead are listed as influences by nearly every major metal and heavy rock band including Foo Fighters and Metallica