Intel to M1 is an entire architectural switch where even old software couldn't be run and had to be emulated.
This is a small generational upgrade that doesn't necessitate an event.
Other companies started having events like this because they were copying apples amazing events. Apples events now are just parodies of what Apple was.
But as someone else noted, CPU power draw is not the only factor in device battery life. A major one, but not the whole story.