Well if the IP is not making money it might be a good idea to sell, but hard to find a buyer.
Selling studios is no big deal if the price is right. Nintendo sold Rare and the right time and MS got like 2 games in 5 years for their 500 million or whatever they paid. I think Nintendo got around $350M for thier 49% stake in Rare.
But I think selling off your developed IPs is a bad move. Sure you get some $$ but also hurt your financials for years to come, just for a short term bump.
Sega could have sold Sonic when their were in trouble, but a merger/buyout from Sammy worked out a lot better for both companies I think.