Funny - I have an email from pg from 2011 where YC didn't fund OpenRent [1] due to our competitors being too dominant.
As head strong (and certainly naiive) young founders at the time, we continued with our vision anyway. Thankfully we have gone on to become by far the largest rental agency in the uk, and have driven real change (see tenant fees ban) in the industry.
I mention this as when it comes to investment decisions, competitors / incumbents of course do matter. But as per what I think pg means here, when running your own business any time spent thinking about the next startup to raise a bucket load of cash is of course wasted. That has certainly been the case in our industry where this seems to happen on a monthly basis.