I disagree, generally it's important to get feedback often and early. Conferences and publications are an important part of the process. That is not to defend the salami strategies of some research labs, but science is moving to fast to wait for your deeply thought out 500 page opus dei, which likely has been obsoleted by some finding published at a conference 2 years ago that you didn't attend.

I have seen the false perception a few times that a PhD is mainly about sitting down and thinking deeply for a long time without talking to anyone and then getting an eureka moment and writing it all up. This is not how most modern science is done (maybe it's still possible if you're a genius in very few select areas of mathematics). So if this is what you think a PhD is about, you're likely not going to enjoy it.