On the other hand, the idea that employees doing one aspect of a company's work could count on being promoted to another area requiring different skills is not particularly common in most industries, pre-internet. Most people who regard doing support as an "in" need to either independently enhance their skills or choose to work at a much smaller company.
One of the sad things that this article exposes is that so many support people choose their careers with the same attitude this article criticises; that support isn't valuable or rewarding to them. Maybe this is akin to people going into teaching, which paradoxically tends to be a major with lower scores and grades than average. People go into a job where they help people not because it's exciting but because they think it's an easier path to working in tech than coding. Great support people committed to what they do can sometimes succeed and grow into more senior roles, and that path should be more rewarded.