To start with my own personal opinion is; free sight-seeing is good for the economy. In effect if you can see something for free in another city or country you will stay longer and spend more overall. On the other hand if you have to pay $10 or more to enter and see any sight you will limit the total amount you spend and the time you stay in the city. The average tourists budget is generally limited and is used for souvenirs and other things as well, not just for sight-seeing.
Let's look at an example. Say you were going to London and you wanted to take in three of the best sights and they were; The Tower of London, The London Eye and Tower Bridge, how much would you pay? The Tower is £19.80, the Eye £18.90 and the bridge £8.00, that's a total of £46.70. It's quite a lot and converts at the time of writing to US $74.40, now it seems a lot more. Apart from the London Eye which is own by a major entertainment firm the other two are government owned and run. So the amounts you pay go directly to line the pockets of big business and directly to government coffers. Neither is good for the economy. Big business cut costs, offer lower pay and cut jobs all to make a bigger profit; and money direct to the government does not create or keep people in jobs. So clearly it is not good for the economy nor the people that tourism is supposed to help.
