Mac minis out of stock because of OpenClaw?

Nah if they are actually out of stock (I've only seen it out of stock at exceptional Microcenter prices; Apple is more than happy to sell you at full price) it is because there's a transition to M5 and they want to clear the old stock. OpenClaw is likely a very small portion of the actual Mac mini market, unless you are living in a very dense tech area like San Francisco.

One thing of note that people may forget is that the models were not that great just a year ago, so we need to give it time before counting chickens.