I don't think of the community as silly or predictable. I do think it perhaps takes itself a bit too seriously, or misunderstands its role in the ongoing functioning of a business enterprise such as SP.
If I'm not mistaken, it is possible to submit legend designs to SP and pay for the exclusive rights to keycaps manufactured with those legends. I imagine the price for proprietary legend designs is steep. I also imagine that not a single community design ever paid for that, which means that despite feeling like owners of the design, you really aren't. You didn't pay for that, and as a consequence anyone is theoretically "free" to use those legends even though they didn't design them. In a sense, you didn't "invest" in SP's legend inventory, you merely failed to lock up proprietary rights to your own designs.
Is that fair? That's an excellent question, and one which designers like Oobly have been exploring with considerable diligence lately. It certainly feels unfair, but as far as I can tell everyone who ever had a design produced signed on the proverbial dotted line and accepted those terms.