So the question is whether it was actually a loss.
OOXML was the other way around: Microsoft had a standard and tried to enshrine into a standard and force others to waste time and resources to be compatible.
That is why I explicitly made references to specific versions as turning points, as I expected the usual FOSS advocacy replies.
Quite often I find that if people stopped holding fundamentally broken dynamics together and just let the thing fail and fail hard, the overall long term outcome would be better off. Much to the opposite of your suggestion.
It's just that turns out, things being properly bodied or properly broken take coordinated action. People deciding one by one, one way or the other, is what actually enables and sustains pathological dynamics like this.
But then how does one single out any specific decision? Well, nohow, not with any rigor for sure.