Because (much like ebay) we don't trust that the reviews are legit?
Well, it's obviously no skin off my nose if you prefer to lump all online reviews together as a class, but I disagree about the seller reviews (versus the product reviews), in particular on Newegg. I've never gotten
any impression that there's a noticeable, let alone significant, number of "not legit" reviews there, whether product reviews or more importantly in this context, seller reviews. Stupid, useless ones? In droves. But "bogus? Not so much. (And I say this as a no-longer-particularly big fan of them in general, between the super-slow "free" shipping and the relative increase in prices over the years... They haven't been my "go to" PC parts/electronics supplier for a while now.)
Over the past several years, the product reviews on Newegg have become increasingly worthless thanks to an ever-growing percentage of clueless reviewers, but if anything, it seems to me that cluelessness has skewed the reviews to the negative. What with all the by-now classic rants about flash memory cards/drives not "really" being 32GB or whatever (or that write speeds are generally a fraction of read speeds), hard drive buyers who brand a drive "DOA" because it wouldn't format without being initialized, not to mention the scary number of people who apparently don't bother with trivia like reading product descriptions and then slam a product when it doesn't meet their (imagined) "expectations"... And it seems to me even more true among the "seller reviews", where people love to bitch that they "didn't notice" that a cheapo product was being sent from China and that it took 3 weeks to arrive, that it's as flimsy as anyone with half a brain would know it would be for the price, or that - gasp - it's prohibitively expensive to return defective products to mainland China and so the "warranty" isn't worth the pixels it's displayed in...
(And for that matter, even on Amazon, where the product reviews have mostly become a sick joke due to all the "verified 'purchase' ", "honest review for free/discounted product" bullshit, the
seller reviews even there seem to me skewed toward the negative for reasons similar to the ones on Newegg.)
As for Ebay, those reviews have been worthless for years (almost two decades, actually, by now - how scary is
that?), but that's an entirely different kettle of fish. At best, they never gave you enough space to say anything really useful and for many years there was the fear-of-retaliatory-feedback issue, and then after
that, the seller feedback became, if anything, skewed to the negative for reasons similar to the ones I note above.