Much obliged means that whatever was done is appreciated. Literally, it could be extended to mean that the person that says "Much obliged" now owes the other a favor. That the one that is obliged is under an obligation to pay back. Most people wouldn't expect a return favor though.
If a man is given a ride into town, when he gets out of the car, he might say "Much obliged". That would mean: "thank you for the ride. I am appreciative"
Someone bound by ones values and word to oblige by providing service and favors
Word component and origin :
(a) Word components of obligent = oblige + -ent (suffix equivalent to -ant, appearing in nouns of Latin origin)
(b) Origin of oblige (verb) is from Latin obligare (ob + ligare) meaning "to bind, bind up, bandage." In modern English means "to put under obligation."
(c) The suffix -ant produces nouns from verbs. It has the general sense “characterized by or serving in the capacity of” that named by the stem, e.g. consultant = consult + ant = one serving to consult.
My dentist is obligent to me for having created his website.
I am obligent to create your social media plan for you
Literally means, "nobility obliges". It's generally used to imply that with wealth, power, and prestige come social responsibility. It's mostly used to refer to the wealthy who are condescending and shower their money and privileges upon those who don't necessarily want it.
Our landlord gave us a basket of fruit for Christmas, as his noblesse oblige.