To be clear, the tweet was claiming that Epic thinks nobody wants to play old games; that wasn't any more true coming from them in 2017 than it was it was when Sony said it in 2013 when people asked if the Playstation 4 would be able to play older Playstation systems' discs.
It is very likely a poorly thought out cover for only wanting the newest UE games to be on the market, though, you're correct about that. At this point I'd settle for a course change and them making the titles as-were available again, because while I'm an admitted supporter of various methods of circumventing a lack of availability 🏴☠️ especially when the corporate suits decide not to play ball 🏴☠️ that shouldn't be a thing people are required to engage in to play older games.