I like to think of this in a different context. Being just a normal employee in a normal job. Suppose you get an idea to make the company more money or to automate all your work. Great. Suppose you even tell your manager your idea. The manager likes the idea but does nothing about it. You're now no better then when you've started. The real magic comes when you have the idea an execute on it yourself. Now when you have a stronger concept that you're ready to demo and show it to your boss, your boss will see you in a much different light. You're not just a worker, you're an innovator that with the right resources, can make the company more money. It's this kind of thing that has the potential to multiply your salary x10.

It's also the kind of thing that has the potential of getting you fired, while they keep the idea and the code.

That's true, but if the company is out to extract your worth and throw you away like a squeezed lemon, you're screwed in this job anyway.

Showing it to your manager will either get you a raise or the door, and if you're getting the door, it's best to add your great cost saving implementation to your CV and find somewhere that'll give you the raise.

Ability to execute is worth more.

Ability to build good product is worth more than ability to build good back end.

Is not a good product a good back end and a good front end together?

Depends on the product, and who defines "good." The back end of most big products you use (PayPal, eBay, etc) are probably pretty "bad" from an objective back end engineer's point of view, but they're "good enough" to deliver the product.

Meanwhile, problems in the front end are more immediately felt when using the product.

Okay, openness is good. But the simple counter-example would be Larry and Sergey's Page Rank algorithm. If they had shared it widely, would they have benefited from it? I think not.

I am pretty sure they published the paper on the implementation before even starting Google.

https://en.m.wikipedia.org/wiki/PageRank#History

Ideas are extremely valuable. They just aren't short term commercialisable. Good ideas prove their worth over generations, by establishing entire industries and not single companies.

If you have an idea which will found an industry (or multiple industries), then you have a good idea but you will likely not become rich from it.

Execution is cheap, most people can execute. Some can execute better than others, but still be unlucky in timing or market. Some people get lucky while executing and thus rich.

If you have an idea which depends on inventory turns (or equivalent metrics), then the execution is important and will make you rich if you get lucky.

Much better would to keep your implementation of your idea a secret. It can be your unfair advantage.

A funny sketch about running out of ideas by Ze Frank: https://www.youtube.com/watch?v=0sHCQWjTrJ8

A secret is more valuable. The reason why is a secret.

Secrets are valuable because they can create an information asymmetry that the holder of the secret can take advantage of. However, it is often the case that sharing the secret is more beneficial than holding it. Which you should chose depends on what you are trying to create, and how you are planning to derive value from it.