The end of the day, sponge wants to be on the correct side of the modding community by abiding to the Minecraft EULA, so selling plugins wont be a thing on ore (not to say that another service would come up that allowed selling - this is what happened with the bukkit api with dev.bukkit being the main place for bukkit plugins and then spigot came along).
As for this community being dead but looks like its active. I beg to differ. I personally am very active on the forums helping where I can, as a result of this i see a lot of questions from developers to be, server owners, etc. with most of the questions being asked by different accounts. While most of the errors are about spongeforge and compatibility with another mod (something bukkit will never do) they are still part of the community.
I also get a few private messages with questions from accounts i dont regonise too, asking for help.
The other thing is Ore itself. It was said on SOS that ORE 2.0 will remove keys, it was then stated “it was a barrier of entry for some people” implying it was too difficult to do for some, so now ORE 2.0 has been released you may see a lot more ore plugins come in. It wont be near the amount of plugins that bukkit has but it should be more