...one of the most salient points is the one you've all raised - that all these author bylines say, "Has been watching movies for 10 years" or whatever - is probably the biggest issue I see with film analysis/blogging/reviewing (and a lot of cultural refraction), which is that there's no sense of discipline or pedigree or even that a critic has "paid their dues." This in large part comes from the fact that the internet has enabled anyone with a voice and sufficient time to bust out these analyses/blogs/reviews (I should know, I have a blog in my signature). It is more important to build your brand than it is to develop the talent you're trying to sell.
I've honestly been bewildered by the social media victories of video reviewers like Jeremy Jahns and Chris Stuckman, which is tangentially related since they're video reviewers, but they're maybe related to this whole kooky dynamic, because if you actually listen to them (as opposed to passively digesting and waiting for keywords like "I liked [X element]"), they have almost nothing interesting to say. Similarly, there's this enormous groundswell of Rotten Tomatoes reviewers who've emerged out of the nether regions of pop-cult media sites, none of whom, again, seem to be speaking with any degree of concision, maturity, or insight.