I think there might be more merit to it than previously thought, but not just for the Scots, much more broadly to the earlier Celtic progenitors of a few later

I think there might be more merit to it than previously thought, but not just for the Scots, much more broadly to the earlier Celtic progenitors of a few later more distinct groups. For example, I don't remember the tribes name, but I recently learned one of the southeasterly Germanic tribes who claimed to be the oldest of the Germanic tribes also said they came from Scythia! I tend to think of the Yamna and Corded Ware a lot when considering this question. While it used to be more controversial, this has also been why the reduction of cost of genetic sequencing has been showing more and more scientifically viable analysis of these types of questions because DNA is much easier to follow! So the Scythians are really just a much younger version of some common ancestors, with haplogroup R1a being one of the more dominant ones. In short, I think overfocusing on the younger "Scythian hypothesis" is too specific and prone to error, but there are lots of great insights to be had in following the genetic maps that have been exploding the knowledge set of proto-indo-european archaeology since about 2010.