Obviously, three different versions of Thin Lizzy touring today can't ruin a legacy because "noone" should/would/could take that act seriously since Lynott died in 86.

And legendary artists that are just going on auto-pilot while still selling records aren't really ruining anything either.

And legendary acts that fall off commercially *and* creatively-I don't think it matters much honestly

HOWEver, a once great act that remains successful-or even become more successful-while putting out inferior material; at least from the ''die-hards'' point of view-I do think that can ruin a legacy even on an underground level.

Rather, it won't ruin the legacy for me but I can understand how it can do it for others, especially those new to the act; they hear some new wack shit and when they listen back to the old classic shit, it may still remind them too much of the wack later shit because of the vocals/vibe/groove/whatever-artists rarely leave it all behind...