I suspect "middle ground" had a race to the bottom on price. I'm thinking for example of Sears "Craftsman" brand. Now that there are all these other big-box stores like Blowe's, Home Despot, they each have to have their own "house brand" that should have been the "middle ground" as well but, as I see it, have moved to lower and lower priced Chinese products.
I think what we're seeing is a nice metaphor for manufacturing in the 1st world in general.
Given the infamous bathtub curve and my personal desire to fix and maintain my tools, getting a cheaper one might be proper annoying. Saying that off-shore T15 soldering irons were a top notch quality often times.
However, for certain types of tools/devices - e.g. multimeter, SMPS (even wall charges) I'd not touch totally no brand. An example of middle ground multimeters: brymen - they are more expensive than UNI-T, better than Fluke price/feature wise and very solidly built. SMPS - meanwell: proper capacitors, creep distance, real copper transformers. Hand tools - (screwdrivers, spanners) - Wera.
It gets harder with heavier duty tools that have to do the metal (like really) - that leaves prosumer+ stuff only - Makita, DeWalt - or straight to the pro: Hilti, Fein.
I think what we're seeing is a nice metaphor for manufacturing in the 1st world in general.