They do, but there’s a trade off. If you go the trade secret route you don’t have exclusive rights.

If someone else figures out how to build or reverse engineer your invention they can do so. If an employee leaks the secret you can go after them, but can’t stop others from using it.

In practice aren't many patents so vague/broad that they are unhelpful in deciphering how to build something?

And don't companies keep various details about how to produce something secret.

It seems to me, that many companies in effect have it both ways.

> If you go the trade secret route you don’t have exclusive rights.

Most patents don't describe in full how the sausage is done. That's been well known for decades now, in various disciplines.