I worked in a Harley garage for like 5 years and I can't say any customer was ever a lawyer or doctor or anything like that. There were a few white collar workers but the vast majority (~90%) of our customers were welders, carpenters, some other sort of tradesman, steel worker, etc. 95% of them were over 50 years old, and I left the garage in 2016.
To be fair this could be due to the nature of the garage, was a cash only type of establishment in a large residential garage, word of mouth only. We still had about 300 customers a year which wasn't bad for a 3 man operation.
But I think the dudes who are lawyers/dentists/whatever that ride Harleys aren't as invested in the culture as the dudes who go to Sturgis and are (in my analysis) blue collar workers.