What _is_ there to protect a person from struggling to spend a long
time developing something up to saleable level, or at least
manufacture level, and then somebody else with more noise and money
simply taking it over?


There isn't any. So what? Isn't the greater good better served by having
innovations quickly brought to market by those who can do so at a competetive
rate? Remember, people innovated long before the USPTO and its foreign
equivalents came into existence.