but even if you collect the tip you still have to live in the neighbourhood and I expect that being a known snitch carries a heavy price.
I don't see how this point carries over to the problem at hand.... what's the heavy price for the scientist snitch?
You're right, monopolies certainly don't drive progress. But the possibility of a monopoly can.
Progress requires R&D, and R&D is expensive and unpredictable. No one would want to do the type of long-term research that invigorates the economy or even creates brand new industries if they won't take in the lion's share of the profits. So it would be a bad idea to implement a policy of breaking up any and all monopolies, despite the fact that it is better in the moment (similar to Newcomb's problem). In fact, we actually institute monopolies using government power, via intellectual property.
It strikes me as strange to designate this as "rational" rather than say, "moral", and then use this as the example of the difference between "rational" and "reasonable". If this is considered rational simply because it's a direct, one-step application of your moral values, then the real difference here lies between your terminal values and the terminal values of the general population; both you and the general population are acting rationally. There are surely better examples to use, where your terminal values coincide with society, and your actions optimize them while societal norms do not. Charity for instance.
For example, it was deemed “unreasonable” to free African-Americans from slavery because slavery was deemed necessary for the economy of the South.
Why do you deem it rational?
I suspect mass-upvoting. Look at the amount of upvotes they've previously got for comments of empty praise