Anecdotally, a pro-audio software company I worked with had to fire 1/3 of the company when their copy-protection was cracked and sales tanked immediately afterwards, and recovered once a new copy-protection scheme was developed and applied. And just to be clear, software licenses in direct-to-user sales are not that company's only revenue stream (they sell hardware and software to OEMs).
This is to say, the evidence in this natural experiment points towards piracy reducing sales by a lot.
Well, "had to."
If it was professional audio, then your main concern would be acquiring business sales, right? If certain companies stopped paying after a new crack comes out then that sounds like a rather blatant example of piracy that could have been pursued legally.
I think the EU study is bogus too. Largely based on questionaires on self-reporting.