> This is noticeable in many other consumer goods verticals, e.g. good luck researching decent home gym equipment that is durable and not overpriced with fat margins.

I think Google dropped the ball on their search objectives in this department. Why is it so bad at helping us search products? If I specify something with 2-3 conditionals why can't it match all the clauses, filter out fake reviews, out of stock, not shipped to my region and such?

They don't want to help us find what we want to buy, they want to sell us what the advertisers have to sell, and the two don't match. They want to sell us things we don't need, this is the reason we never buy anything from the ads and their whole industry is a scam.