This is very much more than just a linguistic little quibble, this is actually a vital point about the economy and the world. Optimum does not mean fastest - nor highest, cheapest, flattest nor any other -est than best.
Just 44 postcodes out of 1.7m are using optimum broadband speeds, Ofcom figures show.
Analysis of internet speeds suggests that a tiny minority of British households are accessing the "gigabit speed" broadband, which is more than 20 time faster than the current average.
Best here meaning the least bad combination of the various different attributes of whatever it is that we're talking about.
Yes, the FT's map of broadband speeds is interesting. But to say that gigabit speeds - meaning fibre to the door - is optimum is to miss entirely that meaning of best.
What is the cost of gigabit speeds? What is the value of having gigabit speeds? Equally, what are the costs of having slower speeds - say using ASDL - and the benefits of doing so? Actual research here seems to be a bit (sorry) out of date here but we can show that 2 Mbits definitely increases economic growth, anything more than that we're just projecting the effects from that earlier proof.
The larger point of course being that in the economy, as with life in general, we've always got some number of competing interests. Price/performance being only one such but an important and obvious one. That McLaren is definitely faster than the Fiesta and definitively more expensive. It's not obvious that either are optimum - depends upon the task. One would be better for doing the shopping, the other perhaps to impress.
So it is with broadband. Faster is nice, sure, but we've still got to ask ourselves what the marginal benefit is as compared to that marginal cost. That's the only way we can work out what is the optimal solution. To forget this would mean that we'd festoon the country with fibre to no very good gain.
And no one would want to do that, right?