I was thing more along the lines of the high power to weight ratio, and the compact size. But now that you mention it, seal technology is much better now than in the 70s. Too many negatives at the time.
Yanmar also made a rotary. For Holy Grail saws of (semi) mass produced saws- Solo Twin BP1 Comet diesel Dolmar KMS-4 Lots of the very first saws, produced in low or single numbers.
Problem with the KMS-4 is overheating. A Dolmar dealer buddy of mine has (7) of them. (2) of which have never seen fuel. I ran a few of them, nothing to write home about. But they sound cool.