Most scientists work on topics that are quite niche. Most of those topics lead to nothing. A lot of good research took years to ripen enough to be of actual value. A lot of popular topics started out in a niche. Most of mathematics took dozens of years to fully come to fruitition. Can you decide beforehand which one will be the next big thing?

Today, most scientists go for the popular topics and whatever is on the government research plan to get funding.* Whenever the wind changes direction they change their topics because they need that funding.

*: This might seem to contradict with the statement that most scientists work on nice topics. But only on the surface. In order to get published you have to do something novel. So, you choose a popular topic and then research a rather unpopular side aspect on it like how a specific chemical behaves when applied to the popular topic. If you're successful you publish and continue. Citations come later or they don't but the next round of funding comes with publishing. After a few years without many citations you move on to the next thing.

On government plans often you need to publish and then it's done. The citations only matter long-term if at all. Most scientists don't achieve anything of greater value. They are happy if they can publish at all. If the institute has a few scientists with a high citation count it carries all the rest of them.