I think some people pride themselves in being bootstrapped, and his point his a bit of investment would probably allow to company to become competitive and the founder wouldn't have such a stressful time while also making more money in the end. So basically swallow your pride.

If that's the message then it seems to miss the motivation for being fully bootstrapped, which (as I see it) is owning a profitable company without outside interests dictating what you do. Given a choice between owning a $X company outright, and owning 10% of a $X*100 company, if both could pay me enough salary to be comfortable then I'd take outright ownership every time. I don't need to be a billionaire, I just need to be free to do my thing.

You can take investment without doing the full seed, a, b, c, d, f rounds. Outside of the hyped startup worlds there are other ways. Or just do an a if you have half of a decent company.

It's someone who loves the sound of their own voice telling some poor person how clever he is and how poor her choices are when she is trying to do something difficult and the one objectively poor choice she has made is the fatal decision to ask the author's opinion.