You're pretty loose with your words here. I'm curious if you've read the RRA you agreed to at any of the registrars you think stole from you.
Registrars ARE in business to generate profit, just like you. You're a domainer. You buy domains for one price and, basically, try to con someone else into believing it's worth more than what you paid for it. How is that any better?
I'm also curious if you read the contracts you agreed to when registering your domains.
I could agree on this. Having 1000 registrar credentials is pretty excessive. BUT, it's their money and they paid for them. I'm not sure if they paid the same price everyone else did, though.
Is it possibly because they had no value, which would be why you didn't renew them to begin with?
I think this has been covered already, here, but most registries set auto-renew by default. This means the registrar must send an explicit delete command in order to cancel that auto-renew. As previously said, the registrar pays for the renewal unless canceled.
Registrars cherry pick the same way domainers cherry pick through available domains or their own portfolios. It's not some sort of deceptive practice. You agree to terms when you register a domain and, by not renewing, give the registrar the right to do as they wish. If you don't agree with such terms, maybe the better choice would be to find a registrar whose terms align better with your ideas.
Your renewal timelines are not arbitrary. As I've mentioned to others, simply read the legal descriptions you've agreed to. Making a profit is exactly why registrars are in business. How much money do you think a registrar makes on your domain registrations, renewals and transfers? Have you ever tried to run a registrar business? I assume the answer is no and, therefore, calling a registrar "greedy" for fulfilling their fiduciary duty of making a profit is a bit irresponsible.