If that's true it's only because most people don't understand these pure maths fields. But their results are generally very useful to the applied mathematicians (whose results are and should be used in most other fields) and in this way there is still an impact although it's not always reflected in the citations.
The fact is that these pure mathematicians could almost surely write the more applied papers but don't because it would feel to repetitive. You don't need to read Euler's work in order to indirectly benefit from it. It's the same for a lot of pure math.
As an applied mathematician, I'd say this depends on the field. Pure maths more often than not comes with assumptions that make the theory more elegant, but by doing so they also drastically limit its application to real life scenarios.
This is not even close. Pure math is often complete clueless about how it applies. For example Developing algorithms to compute properties used in the most basic pure math is a massive pursuit.
The fact is that these pure mathematicians could almost surely write the more applied papers but don't because it would feel to repetitive. You don't need to read Euler's work in order to indirectly benefit from it. It's the same for a lot of pure math.