"However, they struggle with growing their team"

it means

"Amazon considers that unimportant and refuses to pay competitive wages"

Amazon had 21$ billion income in 2020, it is not a tiny company struggling for resources. ( per https://en.wikipedia.org/wiki/Amazon_(company) )

Why actually and not just confirm? Also, investing in something internally means absolutely zero as none of those investments seems to have paid off so far, since there has been absolutely nothing deployed or done by Amazon in public to fight the review spam.

I've seen other people say the same thing about fraudulent products but amazon hasn't taken the most obvious step, stopping commingling products, there. This makes me believe that they aren't serious about that issue and I don't see why I should believe they're serious about this one either.