Apple is a trendsetter, though: I think, as a rule, Apple’s decisions are copied by a large part of the market so its market share isn’t an adequate measurement of its influence. This will be especially true if Apple Silicon MacBooks are impressive in some way, like extra-long battery life.
Absolutely, better performance per watt means longer battery life. Windows already supports ARM. Microsoft doesn't really have a choice here but to improve support for ARM. Office on Mac seems like is going to be ready for Apple Silicon if that effort also helps Office on Windows ARM then they are half way there.
