Gmail is using their influence to modify email standards[0]. This is exactly how it works in reality. If a certain service provider holds most of the user base, they can implement breaking changes without fracturing the community. In some cases it's a net positive, helping protocols evolve, and in some cases it's a net negative.

[0]https://www.theverge.com/2018/2/13/17007100/google-amp-gmail...