The example I quoted was from one site, there are over 350 known faking sites in the Langdale area. Add the other Cumbrian sites to this and you start getting a picture of large scale production
75000 a year was considered possibly an underestimate as it was looking only at the material in the one scree and didn't take into account the material that had slipped or weathered away.
So using your estimate you should be looking at 40 - 75 individuals per site. That would take your workforce to 14,000 based on 350 known Cumbrian sites and 40 individuals. Some sites are quite small scale so maybe we should half that number. That leaves us with a Cumbrian workforce of 7,000 based on your figure
Clough has identified 34 distinct axe producing areas (not including flint producing areas) throughout Britain.
Add to this the folk who are distributing the axes and the people who are servicing the trade routes e.g. boatbuilders etc.
I think the figures are reaching an industrial level - Not many current British manufacturing industries have that size of workforce.