My greatest fear when it comes to The Elder Scrolls and Bethesda sandbox games in general is that some day I might wake up to a Beth announcement that they will no longer release a construction set for their games.
It would be a huge loss for me personally, as Bethesda is all I have to turn to for PC games these days with every other developer being prodded into 2-3 year development cycles by their trash publishers (Activision, Nintendo, 2K etc) that spawns games for the masses. I don't want that to happen. Now, I think Bethesda/ ZeniMax knows that their CS is what keeps their games successful on the PC, but in case a hostile take over happens or any other unforeseen apocalyptic event, what better way to say it than in green numbers on the quarterly report?
Zenimax is privately held so a hostile takeover isn't really possible, and there is no need to appease stockholders interested only in short-term profits with numbers on quarterly reports. When you're building franchises for long-term profitability, you make different choices than when you're milking them for shorter-term gain.
By fostering an active community the CS greatly increases the legs on Bethesda games. Not only do a number of console players eventually buy a PC copy, but the longer a game enjoys an active community the longer word of mouth is likely to attract new players--both to their TES and Fallout games. After a bit of initial experimentation with item packs (horse armor, spell tomes), Bethesda also seems to have settled on forms of DLC that are not primarily candy stores, so that the CS doesn't threaten competition in the same way toolsets do with some franchises. It's also named for an Apple construction set Todd had when growing up. A feature as popular as the CS, with as good a business case for it as the CS has, that devs are interested in including seems to me really, really unlikely to go away.