Yes, patents are relatively expensive. Particularly, if using an attorney to do the legwork. But, they are very strong to the point of where nation states will actively embargo imports of infringing items.
The PVPA fees amount to approximately 5K in total for a successful filing (from what I can tell). So, still pricey, but a more reasonable expense for that "unique" cultivar. There may be discount for small entities, I do not know. And, of course, you would need to understand the guidelines of what would denote a successful filing.
True and relative. Business decisions. Companies have thrived and failed on such decisions.
The alternative mechanism to protect yourself from being "blocked" (the vocal concern) from utilizing your own unique strains is "prior art". Simply selling an item will establish prior art. Not the best way, mind you, but it is defensive.
Prior art will not provide protection from others "copying" or reproducing the genetics but it can prevent others from establishing a claim through patents or PVPA.
There are good ways and better ways to establish existing/prior art. Cost to establish prior art would be relatively inexpensive but you do not gain the exclusivity protection.
I don't know what other ways, from a legal standpoint, that a breeder could pursue. Wet ink contracts between two parties that prevents the dissemination of genetics to the larger public would be one mechanism. But, even then, there are potential for problems. E.g. is one certain that no seeds have found there way into the end product ,etc...