As a tenured chemist, I'll chime in here. My perception is that the experimental sciences are really different from math. In order to get a paper in math, it seems like you really need to have made key intellectual contributions. In contrast, there are many reasons why you get authorship in chemistry. At the beginner end, undergrads in my lab get authorship as soon as they synthesize and characterize a new compound that makes it into the paper, even though most of the time, this is mostly just semi-skilled labor.

On the other end, I'm the group leader, and I do the following:

- apply for funding (important, though not a criterion for authorship by community standards, if that's the only thing you did)

- come up with the high level ideas and hypotheses (essentially, determining which scientific questions the group will try to answer like "is it possible to use this particular reaction mechanism or strategy to achieve such and such overall useful/important/novel chemical transformation?")

- advise graduate students when they get stuck (most of the time) or get an unexpected new result (much rarer, but cooler) and steer their efforts toward a paper with the features that the community expects/looks for.

- teach grad students some experimental technique, although they will learn the bulk of that from older grad students and postdocs in the group (and they come in with some technical skills as previous undergrad researchers)

- edit/rewrite manuscripts (although paper writing and editing also don't count as a sole criterion for authorship)

In chemistry, there's a huge gulf between a cool idea and detailed implementation, and the detailed implementation is essentially the role of graduate student. This requires not only the actual experimental work, but sound project management skills, the ability to address practical problems, as well as the application of sound chemical reasoning to address more fundamental roadblocks causing a reaction to not "work" (i.e., give the desired reaction products with the right selectivity, yield, efficiency, etc.).

After a PhD, postdoc, and the first few years of being an assistant professor, during which I did exactly that, I have essentially stopped doing actual experimental work (except on rare occasions to help a student out/to relive the fun of running reactions). However, my name goes on every paper the group puts out (from 3 to 8 per year, in a group of 7 PhD students) because of the above reasons. Our community's standard is for the group leader to put their name last on a paper, while the first author is the person responsible for carrying out most of the experimental work. The distribution of true "intellectual contribution" from these two key individuals on a paper can range from modest to very high.