That's not how competent research is done. You don't go into a hole for 5 years and then come back into the world with a fully-formed paper. While you're doing that research, the world moves on, and if your citations are from 5 years ago, any publication will ask the extremely appropriate question "How does this matter w.r.t. the research published since you started this work?", and send the paper back for rewrite. Or, it may ask the even more appropriate question "Why does your research matter given the results of papers x,y,z which are directly related to your research question?" Any competent researcher should preempt in their literature review, and if they can't then it's not research but instead PR.

And this doesn't even touch upon the fact that research that's going to take 5 years is going to be well-funded, and you'll have to write interim reports over that period. When you get 5 years of funding, you don't get that all at once. During that time, you'll have to answer for advances in the field and justify why the research is still worth doing.