Many people start blogging when they heard that it could bring in cash. They blog day and night, 24/7/365 (that's it, 24 hour a day, 7 days a week, and 365 days a year). Finally, after some months have passed, they generate less than, maybe, $5 a month. And then they got bored. And quit. So what's the use?
Inevitably, the bloggers who blog for money, be it to write reviews or publish ads, will find that blogging is nothing more than a tedious work. They will fall short of energy in no time. On the other hand, bloggers who blogs for their blog (get it?) will rarely quit, as they love blogging. I didn't say that you can't get a handsome amount of profit from your blog, in fact there are many bloggers that are wealthy beyond imagination (hope I didn't exagerrate). It's just hard to maintain quality works when we aren't really enjoying it.
As for me, I consider sharing things through my blog is a payment for all the Internet services that I used (emails, Facebook, YouTube, Messenger, etc) but you are welcome to differ in opinion :)