"...We've had to pass on some amazing engineers just because they did not have the rails web, front or back end experience. "
Why would anyone want to work with amazing engineers?
Why would anyone want to work with amazing engineers?
You shouldn't be hiring people because they have experience that matches your tech stack solely because they'll kick ass on the first week.
You should be hiring people that will kick ass 3 weeks in, and a year from now, and 5 years from now -- regardless of whether or not they currently have competence in the nitty gritty details of whatever libwidget you use at this exact moment.