There are in fact theater lights at least as early as the 90's with cold mirrors to direct IR to a heatsink, to extend the life of gobos and gels, and put less

There are in fact theater lights at least as early as the 90's with cold mirrors to direct IR to a heatsink, to extend the life of gobos and gels, and put less IR on actors. Cold mirrors that large are expensive and it's just complexity/something to break or need servicing (cleaning) so I doubt they were stocked much by rental companies or saw much usage in tv/movie production.