There's some truth but also he's taking the case of Completely Motorbikes and rolling it out over the whole industry.
CM had a lot of dealers, so with them passing into Administration, a lot of dealers all over the UK have closed. Some of them will return, as the administrators find buyers, so I don't think things are as black as he paints it.
Also, some brands are currently falling out of fashion, I believe KTM are not as popular as they were, so that won't help, but at the same time... the Chinese are coming, with Voge and CF Moto (yes I know the tie up with KTM), selling pretty much everything they can make.
With all the expensive bikes sold under finance deals, there is a strong possibility that people are waiting to see what happens under the new Government with regards to inflation, wages, interest rates etc.
Maybe the industry is shrinking, but if it can survive all the covid lockdowns and restrictions, I think there is hope for it yet.