The general consensus from what I've seen posted here and looking around at other sources is this: ROMs are only legal if you've created them yourself from your original copy of the cartridge/disc/media. Anything else is considered a violation of copyright.
Whether or not companies care about old games being distributed is a matter of opinion and a decision each company will make on its own.
As always, direct links to any sites distributing ROMs or asking for such software is against forum rules.