Then there's the one or two sites where actual experts spend time and effort to review things in a thorough and unbiased way mixed in with 20+ review sites that look like they're legit ones but have no expertise, spend no effort on reviewing, and are just there to earn money from ads and affiliate links.

Unless you're an expert, or you spend a lot of time and effort, you don't know which sites are legit reviews and which just look legit. If you are an expert, you probably don't need the sites.

What makes / made Reddit valuable is that there were communities where experts hung out and posted opinions, not because they were getting paid, just because they were interested in the subject. Not being paid was a double-edged sword though. It means that the person isn't biased by money or trying to earn a commission. OTOH it meant that they had no incentive to be objective, to be helpful, and so-on.

It meant that one dude who had had a bad experience with a windslapper was motivated to bring up their bad experience whenever the subject came up, but wasn't motivated to post to actually provide well-rounded advice when people were just asking about helmet recommendations.

It doesn't help that any attempt to create a "seal of legitimacy" or something for a review site is always co-opted by the brands who have a vested interest in moving their own product.