The engine monopoly point has been kind of stupid for a while now. Blink is open source. It's a stable target. It's not vendor-locked. There is no problem with it having a monopoly, and I am sure the industry can decide to fork it or start over if the leadership goes absolutely cuckoo. When it comes to good open source projects, we WANT to be converging on that one leading project and ensuring it's the best it can be…
You are essentially arguing that a monopoly position in this particular industry minimizes what is known as "welfare loss". That would be quite an exceptional claim, IMHO
This in general only happens within market areas that appeal to the formation of so-called "natural monopolies" - typical examples being water, postal services, electricity, and the like (utilities). The rationale being that the monopoly formation in this case spares society as a whole for excessive costs as these industries are characterized by a very high proportion of fixed costs (infra, machinery, ect) relative to variable costs.
With browsers it seems that on the contrary the overwhelming majority of development costs are indeed variable (man hours) which -- all else equal -- would support the assumption that competition in this market would be better for society as whole, and that a monopoly here would be a loss for society (and eventually it would fall).