This is a community of amateurs, and with some discipline you can definitely rely on their (our) conclusions. While amateurs lack training, they also lack financial motivation. Sure, confirmation bias exists, but amateurs are happy to tell you which of their headphones sound the best and reviewers never will.
The best way I’ve yet found to evaluate gear without hearing it is to befriend someone with good ears who buys everything, then just ask them what they like. That’s the real end game.
Its not that i feel the need to defend myself or argue with you since you are right in a way but your arguments are not very strong. I can shoot holes in them all day long.
This might have started as a community of amateurs but i see plenty of (welcome) professionals contributing. And even when they have obvious financial interest i never suspect them of having any other primary motivation than the love of good music (reproduction). If you go into hifi to get rich you're an obvious idiot (excusez le mot). Yet there are entrepreneurs blinded by the prices of 'high end' gear thinking they can make a profit; I'm not going to speculate further...
Often the word 'amateur' is perceived as 'not professional', hobbyist, easily mislead, newby, only aware of the basics and even 'loser' while originally it just means 'a lover of...'. So I wouldn't use it as you do. Professionals love they job too. Most often they started as amateurs. Amateurs can be ignorant or dumb without anyone holding them accountable. Professionals are held to a certain standard (that's capitalism 101).
Who says amateurs have no financial interest and why would that be the sole or foremost cause of bias? They are biased, I have met plenty of 'amateurs' who clearly are (fanboys). Irritatingly so. That is not just 'confirmation bias' but can be anything from belief in science (scientism), trust in commercials, nationalism (!), bad experience with some retailer or factory customer service, nostalgia vs futurism to plain snobism.
As to your last statement: that friend with good ears won't buy just anything either. He thinks before he buys too. And they have preferences. My old dealer/retailer did that too. I could trust him blindly (still do) because he has integrity and a love for music just like i do. And i consider him a friend, not just a box grocer. So how do you know who to trust?
So i understand what you are saying but it's just one way, hard to find someone like that. Unless you mean me. I buy anything i have confidence in and try it. And i will tell you what i like. I'm an amateur but I'm not unprofessional.
Here's a good analogy; when you go to a football game: who are the amateurs and who are the professionals? The fan(atic)s in the stadium love the game. But more than the game they love their club. They will stay fan whatever. Whether they win or lose, regardles of performance. And the players get payed according to their worth. They switch clubs when they can if they like. They love the game too but they are way more objective. Or you can say they are opportunistic and follow the money. But if you ask them what club they like best they have perslective. But have you ever seen a fan switch loyalty following performance? You think a fan will ever - only- consider performance when speaking about the 'competition'? Its always the total experience: city, culture, rivalry, friendship, peer pressure /groupthink etc.
In short: better the devil you know...