It's easy to pivot when you don't have a product that people use. I'm sure many people on HN (myself included) have pivoted several times in the last year as well. Assuming one of their projects stick they'll become less agile. Unless they are just interested in being a flip factor.

As much as I hate buzzwords, I'll play along for the analogy:

You can't 'pivot' if you don't have any feet on the ground. If you have no real direction or dedication, moving to something new isn't 'pivoting', it's defining what you're doing in the first place.