You just moved from "market leader can dictate the standard" to "market leader can dictate what developers will want to target".
But with that premise, having a standard or not doesn't determine the outcome. Market share determines the outcome. The standards are just recommendations, nothing forces Google or anyone else to implement them.
Let's just go with something simpler: Google having the control it has on the implementation (and thus, most everyone else because to make a useful browser you have to make it mostly compatible with Google's implementation that everyone will target) is bad.
