Someone will pick up the slack.
That would be fine by me. I write software either because I enjoy doing it, or I earn money for it, or both. I'm writing/maintaining cgminer because I believe in bitcoin and I like to earn bitcoin. I unashamedly wrote the scrypt support for a generous bitcoin fee a long time ago so it was purely for the payment. I have no interest in altcoins so someone else
should be maintaining it. Just because others have an interest in altcoins doesn't mean that I have to.