You’re looking too narrowly. By getting devs to cater to whatever gets rolled out in Blink and v8, google extends the power they have over the whole ecosystem by making any browser that doesn’t follow them look “broken” (as opposed to, not slavishly following everything google does).
It also increases the difficulty of making a competing browser engine by adding tons of complexity (for questionable value), only further entrenching google’s dominance. But at least you get some stupid new CSS3 behaviors (that people will bitch about not working in Firefox or Safari) so I guess it’s worth it.
It’s 100 guys, I don’t think anyone is especially concerned.