Note that the comparison (more to do with X than Y) isn't very helpful for cases where X and Y are not exclusive, and/or related.

I find it helpful to model salary as

(value contributed) X (percentage extracted through negotiation)

in most cases. For a huge swathe of people a marginal hour in negotiation is worth much more than a marginal hour in contributing value. And "a marginal hour invested in Y produces more than a marginal hour in Z" is very useful information.

Also, 5 minutes of salary negotiation is bull crap. There is no excuse not to spend dozen hours of research and have multiple 30 minute conversations every year or two. Of course, you should put the same level of thought and effort into other areas of job-satisfaction (commute, hours, duties, etc.) as well.

I agree that you should be willing to spend a lot of time on negotiation, but would like to clarify that investing even an hour is often exceptionally valuable.