Yes, that switch (and the fact that could even be done) makes their case much worse, that's for sure.
No it doesn't. POS still requires validators to have hardware, software, and sweat equity to make it operational and maintain it. It's no different than a POW miner who has to clean his rigs, cool them, etc. I mined Ethereum for years and I had to monitor the rigs daily, reboot here and there. Upgrade mining software. I had a few GPUs fail and had to RMA them, etc. The majority of ETH I obtained the same way Bitcoin miners acquired their BTC. But you bought your BTC and did zero work mining or developing it.
So the SEC argument that you expect to profit on the work of others is actually valid for both you and Saylor.
It's is 100% a fact that the Ethereum project has been the hardest fought with blood and guts in the trenches work, compared to Bitcoin. If you tally up all the manhours that went into the Ethereum project it totally eclipses what went into Bitcoin's development. The Lightning network is apparently also a mess and never really fulfilled it's promise.