Diamond Geezer has been blogging for years and definitely understands what a high street is. In fact he’s probably planning a follow-up already about High Roads. (There’s already a visit to the shortest high streets as a follow-up: https://diamondgeezer.blogspot.com/2024/06/londons-shortest-...)
Streatham High Road still seems like a grey area that should be considered a high street.
It probably was a road (connecting 2 towns with no houses) when it was first named, but is more of a street (with housing either side) now, and is definitely the primary commercial street in Streatham.
That's a pretty misleading way of explaining the term. It's certainly not an unalloyed positive. Urbandictionary or similar might give a broader understanding.
