That... Just sounds like a horrible implementation/engine/execution/strategy whatever you want to call it.
I don't see any reason whatsoever that a temporal workflow composed of activities would be subject to the things you've described. And I don't even think it's that impressive of an implementation of the idea.
And that sounds like a no true scotsman criticism. :D
My complaint was less that it isn't a compelling idea. The problem seems to be that people want to expand the one system they are working on to be a fully comprehensive system. I remember one team tried to get their entire state reflected in a Step Function state machine that could run for as long as necessary. Idea literally being a state machine that would last years or so. They compromised for one that would only last a week or so. And then faced the consequences rather quickly.
And note, given enough time, I think this can work. On a deadline, though, I've seen it fail too many times for it to be my goto solution. All the time by people that are objectively smarter than I am.
I don't see any reason whatsoever that a temporal workflow composed of activities would be subject to the things you've described. And I don't even think it's that impressive of an implementation of the idea.