You have missed one of the two fundamental reasons we preserve a culture. We value diversity. We recognise the dangers of uniformity. We understand the benefits that can flow from variety. We are smart enough to understand that the ultimate value of preserving cultures will exceed the tiny amount of money we spend on doing so.
What is this ‘ultimate value’? There are probably several, but the one that seems most important to me is that a preserved culture offers living evidence that there is another way of doing things. Recognising that there are alternative lifestyles, optional behaviours, different technologies and diverse ways of interacting with the environment is key part of maturing. Some people – and some cultures – never achieve that recognition and they are diminished as a consequence. Having accessible, preserved cultures makes that recognition much easier to achieve.
The second fundamental reason we preserve a culture has already been mentioned: guilt.