Actually, now that I mentioned it, I'm curious what they were going to do with SCL if it was successful. I mean, it seems like they wanted it to be important, one of the tag-along NPCs appeared on the cover of the SCAG, and its BBEG is listed as a possible fiendlock patron. The obvious answer is "expansion packs", that would follow along the storyline of the hardcovers, but would they have done more to incorporate it into their core?
The Neverwinter MMO is part of their multi-media franchise, but as far as I can tell its presence in the 5e family has never been as heavily sponsored as SCL was. I don't recall seeing any statblocks of major NPCs being made for it, I've never seen a book that explicitly stated it expanded upon or was expanded by the Neverwinter MMO (though maybe the Neverwinter campaign guide in 4e did). The most I've seen of tie-ins was that it appears in Dragon+, it gets a mention for storyline stuff (Oh Cryptic is doing this for the Neverwinter MMO!), and I got an item coupon when I bought the Elemental Evil board game. I don't seem to recall there being anything else, aside from maybe item coupons in other D&D non book items? Whereas I have seen all of the above (except for item coupons) for Sword Coast Legends, which maybe implies that wotc had bigger goals for it than they did Neverwinter.