Earlier quoted context omitted.
Which is the worst, unforgivable sin (even worse than being old). It doesn't matter what you have done, if there is no corporation to witness to your ability and you do not have a fresh face. Hence "entry-level" positions requiring 5 years of experience, and yet you are unemployable forever if you don't have a job within 5 years of graduating. It might as well be law.
Is having corporate experience really that much better though? I mean, obviously working for someone for several years implies some level of competence, but your work is nearly always locked away and you can't show it off. Ideally you'd want someone who does both; working for someone, which demonstrates the ability to work on a team, while also contributing to open source and making their own content, upon which you…
Yes, a thousand times yes. At a minimum it gives you insight into some product/set of products that are commercially viable and people use. You get experience with at least one build system, and code architecture someone took to market. It also gives you a paycheck that frees up worries about food and housing. In the least demanding of these jobs you can use the down time to learn other technologies by building a MVP of the current product in another technology or contributing to open source projects your corporate job uses. The insight gained from one "real job" is a million times more helpful than trolling github and trying to figure out what a given project is used for in the real world.