For example Stable Diffusion is based on the LAION datasets which include billions of images scraped from the internet. So Phillipino culture is likely underrepresented on the general internet and the models don't have a good representation of them.

People take the trained models and add stuff that wasn't in the training set, e.g. you can train on images of 1600s philippines to get what you want that is currently missing.

Have a look here for some custom models, people have added styles, concepts, people etc: https://civitai.com/, you could easily make one that does historical periods from all over the world. I'm sure people would love it.