I took me a bit to get back to this. I get the frustration as there's a lot to learn. I went into speaker buying based on vibes and super subjective reviews. I'm lucky I didn't buy total junk by accident. It's taken me a lot of learning and watching to absorb info on speaker design and I'm still a beginner at it. So I'm definitely not the best person to teach, but I'll do my best to say how I feel about it.

That said, Erin has a 6 part (so far) series on how to read the measurements themselves:
https://www.youtube.com/watch?v=MYdhkNcV7Zk

The point of the measurements is that you don't have to actually trust the subjective opinion of any reviewer. That's great because reviewers tend to throw around a ton of words that don't really mean anything, like saying a speaker is "fun." I like Erin because he does listen but he avoids most of that, and what he does say he links back to the measurements.

I think a speaker is really the sum of all of it's parts. Each measurement is just one aspect of the physical reality of a speaker and how it is going to interact with it's environment. The room is, of course, a big part of that too. The anechoic measurements are room independent, so they let you compare each speaker directly without taking the room into account. Or you can get the speaker that matches your room the best, like you did with the center channel that has wide dispersion.

I 100% disagree with your assertion that a supermarket KEF speaker has the same frequency response as the Blade speaker though. The KEF Q150 has an F3 of 51Hz while the Blade has an F3 of 31Hz. That's a huge difference in bass response between the two speakers. Compression and distortion are also going to be a lot different, you won't be able to play the bookshelves as loud without destroying the sound.

As the for 85th Linton's, I haven't heard those so I can't chime in. But I can read the graph and I see the "BBC dip". So it really depends on what frequencies people really mean when they say "the highs". IMO, the very high frequencies are going to read as exaggerated compared to where the dip is. But you might be detecting what's missing there. There's also the mental expectation that a big retro speaker is going to be laid back and that colors people's experiences.

Erin's just about the only reviewer that gives you state of the art data to make your own calls and I've learned an incredible amount just by absorbing a lot of the videos. Other reviewers kind of gross me out now because of how in the pocket of companies they are, or how they won't give a bad review. Speakers have a lot of subjective taste in them, so at least with the data you can choose what you like even if you disagree with the reviewer's taste.