Companies figure it’s cheaper to bribe/pay a small amount to a bunch of influencers instead of a lot to a single advertiser (TV, newspaper, magazine, etc).
These days all reviews are fake in their majority. I received plenty of “discounts” to post a positive review. Imagine those influencers with huge followers. YouTube channels with 250k to 500k receive around $3k to advertise a product/service.
Apple sends gifts and invites to events. If you write something negative (like iPhones having a low 60hz refresh rate) and you’re out.