That is a interesting observation. yeah the 2 stroke engine have grown huge and became quite powerful compared to their older smaller cousins.
it used to be that a Saito 80 competed against the .60 2 stroke engines. Now the large 52 and 55 two stroke engines are almost as powerful as the .60 engines. So actually the  Saito .82 is now competing against large 46, 50, 52, and 55 engines. You have to go with a .90 to 1.25 four stroke to compete with the more powerful .61 size two stroke engines.

But now in recent years, in a effort to reduce the noise, the two stroke engines are being tuned to turn slower RPMs as a slower larger propeller makes less noise. Plus they are using much larger mufflers than the engines did in the past. All to reduce the noise levels being outputted by the two stroke engines. So the two strokes are more or less becoming more like four stroke engines. But still a 2 stroke is putting out between 40% to 60% more power than a same size four stroke engine can. Which means you still have to increase the four stroke engine displacement to match the smaller two stroke engine.

I have been impressed with how Saito has managed to reduce the weight and size of their newer four stroke engines. I have a couple of Saito FA-40a engines, and they weigh slightly less than the Thunder Tiger Pro 36 engines do. But a lot of weight is arguably in the huge mufflers that the two stroke engines use nowadays to get their extra power with. But the TT Pro 36 still outpowers the nifty little Saito 40's by quite a bit though.