But if you did a lot of things you might know what does not work and why. Similar to science articles, nobody talks enough about "X technology does not work for Y domain", so a lot of people try to "reinvent the wheel" only to realize "X does not work for Y". Occasionally there is a surprise (because of some technology advancement) but being old definitely gives you more insight in what can go wrong.
At my current job I work with several people who have one to three years of experience repeated over the span of twenty. It might be less likely than some parts of HN would like it to be.