I wrote a tiny app in flash / AS3 back in the day, a CAD floorplan viewer in a few hundred KB, including baked-in artwork and font. CPU and memory use was quite low. I never considered flash to be bloated or slow. The way most people used it made it bloated and slow, with heavy software-based vector animation, tons of video, and flex. Flex was very developer-friendly but also quite bloated, so I never used it.

I wonder if electron is a bit of the same deal, with the recommended way of using it optimizing for developer efficiency over resource efficiency.