Why do lagers get made in tropical climates? Lagers traditionally were made in the colder months and stored (lagered) in caves. As lager yeast prefers a colder fermentation and conditioning temperature than ales, why is lager regularly made in hot, tropical climates around the world instead of more temperature tolerant ales, or just imported?

On a tour around the Tiger Brewery in Singapore where the average temperature is 30 deg C, the guide mentioned the brewery started in 1932 and used a "tropical lagering process". The guide wasn't sure of details, and I haven't found details elsewhere on this process.

Is it a simple matter of economics, that it's cheaper to brew lager locally even with climate control than to import, or is there a way to successfully brew lagers at high temperatures?
It's just marketing.  

Lager fermentations are very clean so it tends to be a beer you want to drink in a warm and humid climate.  The breweries want to make beer that will sell very well locally, and that just happens to be lagers.

At a commercial scale brewers are investing in temperature control regardless of ale or lager, so it's not a significant expense or savings one way or another.  So since they're spending the money anyway, might as well brew what people will buy more of.

From the consumer perspective, it's cheaper to buy from a local company than it is to buy an imported beer in most cases.  So the local beer sells better than the import.