This feels like the sort of advice that increases the variance of outcomes more than the mean , if that makes any sense. It'll help some people, but also really won't help others. It's like... You'd need some serious disregard for the rest of the physics community to think you can figure out a reactionless drive. This is great if you actually can, but otherwise it's going to lead you to failure. In a lot of ways, get…
I think it would be very desirable to increase the variance of outcomes without significantly decreasing the mean. The way research funding is structured now, researchers are incentivized towards taking small publishable steps without too much risk. This is needed of course, but it isn't going to bring about another Newton. I think we desperately need a few more Newtons if we're to prosper in the next hundred years.
I often wonder how much this applies today. Academic science is currently heavily driven by funding of popular, low-risk research.
Also, without meaning any disrespect to Feynman or the advice, it's easy enough to say something like "disregard what others are doing" when you've won a Nobel. It's another thing to say this to people in just about any other inequivalent scenario, which is nearly everyone.