They are stealing from you. As you point out you go out of your way to help companies with your oss options: you’re way on the right side of principled and generous. this is abuse. Don’t put up with it.
Given the history, I’d suggest a short C&D recounting the 10 years(!) of theft, the measures they’ve gone to, and tell them they have 15 days to either stop or get licensed, or you will seek 10 years of back licensing, interest and penalties. I assure you that you will receive a call from someone. Especially if you have to turn the software off on day 16.
Anyway this seems substantial to me, but also there’s an ethical and philosophical question of responsibilities. Do you have more responsibility to your employees and shareholders or to this space company? Even if you’re crazy rich as a company, I propose as the CEO you owe a pretty strong duty to those stakeholders to try and recover stolen assets. You don’t have to be mad at random spaceco, but I propose you might think hard before walking away.
Quick edit: just to frame your head on this: If the company is in the US then this behavior likely falls under DMCA anti-circumvention laws. if it does, people would have criminal liability. Now, I believe the DMCA is terrible legislation; it lets corporations create criminal liability through license agreements. But, it is the law of the land here, and I would guess as soon as your attorney can lay this out, and their attorneys get an eye on it, you will find willing negotiation happening.