Disclaimer: Never been there myself, and I've never been an official reviewer for a journal.
In general, combining different fields is seen with good eyes, and should be done by researchers all the time instead of reinventing the wheel on each field. Terence Tao is well known for combining different fields of mathematics in his research.
That being said, a paper that combines tools and concepts from very different fields, and specially fields that have different kinds of people (i.e. economics often attracts humanities-oriented people, who despise deep mathematical theorems, while pure mathematics sometimes attracts people who dislike subjectiveness). Then reviewing a paper such as yours requires a lot of effort by the everyday referee, who usually only needs to learn about the precise contributions of the paper he/she is reviewing.
By tools you mean mathematical tools? Software tools? Reviewing code is borderline unthinkable for people in several humanities fields, specially more experienced folk who never had to write code for their research before.
On the other hand, maybe if everyone in economics fails to understand (or is not willing to go through the effort of learning) your tools, you might have a very confusing paper in hands that no one believes is worth the effort, so you might actually have a presentation problem: Your paper is hard to read because of style/clarity reasons. So a not-so-lazy reviewer thinks the lack of readability is meant to hide poor content. Thus, he/she concludes it is not worth the effort of taking a course on the tools you've used only to review the paper. Maybe the results you present are also not-so-great, which would make the paper still valid but demotivates the reviewer as well.
The suggestions I can give:
If you are allowed, publish the code for software tools, or maybe for some mathematical tool, publish code that proves them. This improves reproducibility of your paper.
Consider splitting in two papers, and submit each part to a specialized journal. So economics people are referred to the mathematical/software paper they don't want to read, while mathematical/software people are referred to the economics paper they also don't want to read. This way you don't ask referees to evaluate what they can't understand. Maybe also publish a third paper summarizing the joint conclusion after these two base papers are accepted, so that their individual validity is much less in check.