1. IMO, a startup who's being held back by a domain shark is already in the wrong mindset and is probably going to fail. Successful startups work with what's available to them and pick up the domain they truly want when they have the capital to do so. Facebook for example, started as thefacebook.com; they purchased facebook.com in 2005 for $200k
2. Yes, .coms are becoming a rarity, but again - free economy; it's all about supply and demand. While .coms may be the ideal domain, it's not like there aren't other completely feasible choices out there. If the .com isn't available, why not .io? .ninja?
3. The drug analogy is incorrect and improper. A better analogy is to think of domains as land. Both are finite in what's usable; and in both cases owners are entitled to deciding what they want to do with the property - whether that's building something, letting it sit there, or selling it for profit.
Don't get mad at people because they thought of your name before you did; accept it as a reality and embrace the practice yourself. A certain founder I know of a publicly traded deals website is sitting on over 100+ domains. Why? The opportunity to use them in the future. I myself am sitting on 20+ for the same exact reason, I recommend you do the same.