all points you mentioned are very true too.
however, those are all related to already being invited for an interview. Selling yourself in a cover letter or CV is a lot harder. That is why I said that having a degree will most definitely help getting an interview. If you are invited for the interview, having a degree will probably not help you much anymore and it is all about presentation, teamwork, leadership and your sim assessment.
at the moment aviation is doing very well and there are plenty of opportunities, even for cadets. however, what if things are not so great? like in 2009/2010/2011. There were still some airlines who were hiring but they sometimes had a few thousand applicants. I am sure that having a degree will help to some extend at least getting that first interview. From then on, you are on your own and you need to suit the company and have the competences for the job as a pilot.