Depends on the publisher.

If they`re one that has a lot of licensed IPs (eg. EA) then it would greatly affect the industry as those IPs started moving to different publishers. If it was one that didn`t really have any licensed IPs but did have some large IPs of their own (eg. Activision) then it would be different as you`d probably see more of a drift in consumers from their major IPs to those from other publishers in the same genre. You`d possibly see somebody buy the fallen publisher`s IPs but they`d probably just end up as a shadow of their former selves and not maintain their current popularity.

If it was a publisher that had neither of the above (eg. Konami) then nobody would give a fuck.

Bet Shiken that COD would outsell Battlefield in 2018.