The loss and ease of mechanical connectors has gotten good enough (0.15 db or better) that most of the folks i know will only fusion splice when they really have to.
I agree it wouldn't make sense to do single pair or single fiber, but that's the actually the comparison at which 10baset-1l is at all competitive.
I have buried a lot of fiber, and a lot of network cable over the years :)
I was just trying to be fair and present the best case for 10baseT1L
In practice you can do 12/24 strand fiber (or 6 strand fiber + power + whatever) for less than the price of whatever particular set of 18 awg twisted pair (which is what the spec requires at 1km) + other things you wanted. The cable would be smaller, and if you use A3 or B3 fiber, it would be more flexible/support a lower bend radius than the 18 awg twisted pair. By far. IT's not even close.
There are reasons why copper and coax exists though, which is what I was pointing out.
Big infrastructure often orders the cables pre-terminated, eg an ISP will order their arial cable with built-in termination at certain intervals. No muss, no fuss.
You're right about single pair though. If you're putting in two strands might as well do 6. If you need 6 might as well do 24. Never hurts to have spares and extra capacity. Especially if it involves stringing poles or digging holes.
I will get pre-terminated for MTP runs, but not for anything else. Fusion splicing connectors just isn't slow (and if i need to go quick, i'll just splice a pigtail onto it until it fails)
I agree for redundancy, etc, better to just add more until loss-of-ROI occurs, but will say doing something for extra capacity for home users/even business users feels like massive overkill these days.
Even 2km 100G duplex transceivers for SMF are <$200 a piece now. Cost is dropping crazily fast. (bidi simplex ones now also exist on fs.com as of a month or two ago, but are still way too expensive)
How much are the termination costs on that fiber, per run?
Also, you'd never install single pair direct burial, and almost never shielded (unless its audio and not phone type) - it'd be 4/6/12 pair direct bury gel-filled cable.