That is a myth. If you know how PR works, you understand that the contribution from a random TC article (not the home page) is not very significant. Also, PR is one in a myriad signals Google uses to gauge the goodness of a page. It's less important than it ever was.
Caveat for startups: most people who mention SEO really have no idea what they are talking about.
Curious why you would claim links for search engine ranking algorithms are a myth. Links from high profile sites (like TechCrunch) are demonstrably good, though I would guess it is definitely a smaller percent now than it was in the early days (ALA PageRank http://ilpubs.stanford.edu:8090/422/1/1999-66.pdf).
If you know PageRank, what matters is not the site that links to you, but the page within the site. Techcrunch.com has a PR of 8. On the other hand, http://techcrunch.com/2012/09/04/gathercontent-launch/ has a PR of 4. That page also has tons of outbound links, so the contribution to the PR of gathercontent.com coming from it page is minimal.
Smaller publishers re-syndicate stories, which means you gather a whole host of backlinks...not just the TC one. Plus the google algorithm is much more complicated than just PageRank. They've pretty much said PR is a small part of the algorithm nowadays.
There are a lot of other signals taken into account, and getting covered by a mainstream blog is a good signal. You benefit from their domain authority even if the page authority remains pretty low.
Did you read my original comment? My point was precisely that PR is not that important. If you want to rank higher on Google, simply create good content. You cannot depend on the signals they use because they change all the time. Do you have any idea if "getting covered by a mainstream blog" is a signal Google quantifies, let alone uses?
The SEO benefit of being linked from a high PR site like TC alone can be worth quite a bit for a startup trying to get a new site ranking well.