Yes it's probable to make gil outside of being a gatherer/crafter. I was originally making a how-to guide as a response. (Denied by character limit). Then later tried making a new thread topic (Denied again by character limit).

The simple answer is, "Yes, just play the market board." However, since I can't fully explain it (nor do I have the patience of making multiple sub-threads). You'll have to read a book on economic trends and analysis. Cheers!