It's more likely they have contractual obligations with marketing companies, retailers, data centers, etc. If a product is discontinued they can get out of those obligations. Sure they will write off a loss and reduce the taxes they pay, but it's not as if a bigger loss nets them more money somehow.

Really what needs to be regulated is all of the excessive exclusive B2B contracts which mean a company can't just sell a product for a small amount of money to someone to maintain it when they're done with that product.