Given their views, I think it's less about paying them money at this point (although you should definitely offer), but more about helping more around the house so you aren't a burden. For example, rather than bring home takeout, learn to cook (a skill you'll need for life as evidenced by the huge money drain on takeout costs while in the apartment - your expenses otherwise weren't high) and cook dinner for them a few nights a week. You can perhaps learn to cook from your parents, making it an enjoyable social activity at the same time. Mow the lawn for them, try to fix the lights, take out the garbage, etc.
I would highly recommend setting a reasonable deadline, for both them and yourself for when you'd move out, because what they say, may not be all of their thoughts, per frugalconfederate's point. (And, just be aware that many romantic partners would consider living at home a turnoff, given the less privacy (particularly for sexy time), awkwardness of feeling chaperoned like a kid, and worries about ability to stand on your own w/o parent support). Read Millionaire Next Door before you make a decision, with an eye out for the discussion related to parents supporting kids.
That all said, I personally think your expenses in the apartment are low - you really just need to learn to cook -- and you gain more from learning to live on your own right now than saving by living with them. I know other cultures vary though.