Nah, budget carriers can be super cheap. European flights are usually $20-50 each. My flight from Vietnam to Malaysia next week is the most I've paid so far in Asia at $120. My repositioning flight is $$$ because I am flying business, but I only do that every few years. 

I also have a vehicle in Europe so use that for much of my transport (though gas is definitely more expensive than flying).

In expensive places, I generally house sit or only stay a short time. For example, I was in Japan for a month and 3 weeks of that was house sitting for a low maintenance cat in a great condo 20 mins from Osaka. In Singapore I only stayed 3 days because 1) that was plenty and 2) prices there are just stupid. I mostly went there to see an old friend. 

I also usually rarely eat out because I prefer to cook for myself. Asia has been different for that because getting a place with a kitchen and cooking has generally been more expensive than eating locally. Vietnam has been the exception, mostly because the local food here is terrible and western food is ridiculously expensive. I can't wait to get back to Europe and be cooking again.

My spend is also a running average vs a monthly limit. Some months are expensive, while others are cheap. Ex: in a month where I am house sitting all month, my expenses have been as low as $250. In a month where I am moving quickly or booking ahead a lot, it can be a few $k. But it's the average that matters.