I didn't mean that either of the companies actually made money from their asset stores, just that a more robust asset store could be an incentive to a small studio. It's really all about saving developer man hours for a highly cash-limited company, and dropping a few k in plugins is nothing if it saves you a couple of man-months of programmer time. I would be very surprised if almost all Unity game releases didn't have something from the asset store. Also keep in mind that, since they don't charge revenue-based royalties, Unity is the cheaper option, assuming that a game sells a non-trivial number of copies.
I'm sure that Epic is in good shape financially. Their games sell well, and their tech gets used in a ton of AAA games, though I have no idea what the revenue mix would be between game and tech. I just meant that their game revenue would be less predictive of value than ongoing tech revenue since, well, games are expensive and can flop. Giant game companies put themselves out of business every year since each release is pretty much do or die.