What does it take to actually learn to play and enjoy.

I wouldn't necessarily say that you 'play' DCS. Some of the planes have a simplified flight model and systems simulations, and those are easier to fly but real meat and potatoes of the game is in the full fledged modules like the A-10c or the Mig 21. Typically these modules are referred to as 'Study sims' meaning that their aim is to work EXACTLY like the aircraft in real life. It can take 10s of hours to get comfortable enough to fly basic missions to their completion, and hundreds of hours to become proficient. That being said the reward is proportional to the work you put in. When you finish a full mission perfectly, or even when you botch the whole thing but limp your way back to base on a single engine and 1.5 wings all the work you put in to get there is worth it.