First off, let me explain where my idea is coming from. After you buy a car it needs maintaining. Now to maintain that car you have two options: You can buy parts from a dealer, or you can buy unbranded parts from a motor factor. The unbranded parts are of a decent standard, they do the job and they are safe. The paint finish may not be as good as the original (but that doesn't matter on a suspension arm, for example) and quite often come out of the same factory. Most people buy non-original shock absorbers. Some prefer to by branded aftermarket shocks, like Monroe, Koni or Spax and in some cases they can be of a better specification than standard.
Lets stick with the shock absorber analogy as we transfer to boats. You buy a Ford car, it will have Ford branded shock absorbers fitted. They are the original equipment, but the manufacturer may not make them, they may buy the shock absorbers in from a reputable manufacturer. When they wear out you may buy the Ford branded part from a dealer, but more likely you may buy a branded non-Ford part, or a completely unbranded part from a motor factor. All three types will do the job they are supposed to do safely. The Ford part and the unbranded part may even be made in the same factory, it's just cheaper because it doesn't have the brand stamped on it..
A boat may be supplied with Harken blocks for instance. When the blocks wear out you may fit the same Harken Block, or you may fit a Ronstan or Barton one instead. What you don't get in the boaty world is the budget equivalent part.
So there appears to be a niche in the market for decent, low cost parts supply, like a motor factors, but for a boat. A Primark of the seas, where low cost parts are sourced and sold. It's even easier than a motor factor because you don't have to stock parts for each model of boat. One cleat will fit many boats, for instance.
Somebody somewhere in the world must be making such parts, all it takes is someone to go out and source them.