Of course, it is not realistic to believe that he will never sell the BTC he bought (and is still buying), but maybe he will sell only a part when the price is such that he will be able to return his total investment, and at the same time he will still have enough BTC left.
Saylor is doing Dollar Cost Averaging for buying Bitcoin and he will apply DCA for taking profit his bitcoin too.
I agree with you that he is smart enough to not dump all bitcoins he has on the market with one order or within one day or a couple of days. Doing DCA for exit price will help him to get better profit by don't have to find market tops and can avoid panic on the market because of selling pressure from Saylor and Micro Strategy.
(SSS) - A Sane and Simple bitcoin Savings plan.
SSS plan looks good for Saylor to take profit.
You both are right, everyone holding BTC including Saylor will try to sell some of the BTC either to book some seed profit or to avoid from taxation, I have read a few times that, Michael used to sell some of his BTC at the end of the year to avoid huge tax that's one of the strategy of him. Well, but that selling did not have that much impact on the market.
And to be honest, I don't think now Michael has any need to sell those BTC because he is already earning a lot, from his company's Micro strategy, but still, he can book some profit but selling all the BTC and going against BTC is not an option for him now. Many investors have trusted him with their money. While they can trust BTC directly but I think people of old mindsets trust people more than algorithms.
Your DCA exit plan looks nice, and OTC trading can also avoid panic in the market, there are many ways if he wants to sell BTC but doesn't want to create huge panic or fud out of it, like he can sell it privately, etc. But let's just not discuss possibilities that are not even going to happen in any scenario. This SSS plan looks old, don't you think?