Your experience is valid, but keep in mind most people don't have that 9 years of experience in a single company to base their hirability on. Employers can give you the benefit of doubt, due to your resume, that you're a good hire. Not so for most younger developers. So what else is there for employers to look at other than proven rockstars and hobby coders?

Keep in mind I agree with you, but I certainly understand the mindset that the parent comment was criticizing.

Well. That's true too. I got my first side project in 1994 because a college saw a HyperCard stack I posted on AOL.

I used that experience to get an internship in '95 and that led to a job with the same company after I graduated the next year.

But after trying to catch up because my "9 years of experience at one company" was really 3 years of experience and the other 6 years was just stuck doing the same thing I did the first 3 years, I vowed never to put myself in that situation again. If I see myself not keeping up technically at a company, it's time to either leave or study and do a side project.

I may never publish the side project and it may just end up being a proof of concept.