Agree or disagree with the following statement.

I have same feeling. Technical data of component gives always me an idea weather it fits or doesn't my system.
There are reasonable judgements on that, there are also manufacturers that reflect and present the actual test data with plots... Another words most of tech data is available from reputable manufacturers to the educated public so they don't have to listen to the salesman and create their own smart home audio/video system.

I total agree with your statement listed above. I was told once before "if you don't vote, you can't have any opinion on politics".

Being rather partial to my money and not enamored of do-overs, I insist on an audition before buying. That said, much can be inferred from specifications, and they are the tools I use to determine what to audition.

For example, I started giving consideration to new 2 channel speakers after finally probing the limits of what my current speakers offer after 30+ years. I very much want to keep a similar tonal balance to what I have, so I know I probably want something with a nominal 8 Ohms and thus somewhat less efficient, a flat response curve, preferably floor-standing, a smaller frontal profile and wider frequency response. So far, I've auditioned B&W 802, Martin Logan Summit X and Harbeth HL5. They have all been acceptable in their own way, but none have caused me to pull the trigger. PMC twenty.26 and fact 8 are next.

My 2 cents, anyway.

I have been in this hobby for 60 years now. I was a recording engineer for many years and I have a BSEE degree. Unless there is something dreadfully wrong with a piece of equipment I have never seen any measurement that tells me how a piece of equipment will sound. Speakers are about the only thing that might have measurements indicating their performance yet how they measure in a lab vs how they measure in your listening room will not even be close. Remember when solid state came out measurements were superb yet they sounded like crap. Digital measures perfect but many people still prefer vinyl. NOS cd players measure poorly compared to oversampling delta/sigma dacs but I still prefer NOS dacs. If you buy solely on measurements you are just luckey if you like the sound. Listening is the only way to buy HiFi equipment
IMHO
Alan

Statement:

"If you have never listened to any particular
component, you can't have an opinion on how it
sounds."

You can always have an opinion, but it you haven't heard
the specific component in question, your opinion is just
that...an opinion. Not very valid in my book.

To add to the above, even if you've heard the gear, all
individual rooms, systems, ears and taste in music are
different. Also most listening biases are different too. So
the only way to be sure is to listen to the piece of gear in
your system and room, with your music and ears...

Posting in these forums are fun and entertaining, but
bottom line if asking "what
speaker/amp/preamp/etc. you should buy is a crapshoot at
best without actually hearing it in your own environment.