I think Social Influencers are the next big thing in advertisers and I can list articles from several reputable marketing specialists that agree on this. The question of whether one can get paid for doing a youtube review is not a question of IF you can get paid, it is a question of how much can you get paid? Free products are a form of payment too. There are youtubers out there that get paid $10,000 for one product promotion video. But we are talking about people that have millions of subs, not a few thousand like me.
I think from a logical marketing standpoint, product reviews are a must nowadays. Many, many leading marketing analysts have made firm statements that "A product without reviews is a product that will not sell." In the modern internet economy, product reviews are the new gold mine. The only question is what is a product review worth to a company. And there are people trying to answer this question with websites like Social Bluebook who's purpose is to give a value to the social influence of a person or a channel. Now obviously, site's like Social Bluebook are in their infancy and are currently nothing more than a hopeful dream, but the simple fact they exist means that efforts are underway to quantify the value of a Social Influencer.
All arguments aside, think about this. Would you buy an unfamiliar product from an online retailer that had zero reviews? How likely would it be for you to buy a product that has not only written reviews but also a video review from a common person (not a professional promoter) that actually shows the product being used in real life situations and compared it to similar products?