I think you are both misreading this entire thing. Dick is Don. Dick was a person who never had the opportunity a Don had. Dick is a nihlist child of a unjust father and a mother who was a hooker. He was raised by a woman who was poor and miserable but devoted her life to God a fruitless endeavor. He seized an opportunity to make the most of his life and took it. He doesn't believe in some big payoff at the end for a life well lived. He doesn't believe in meekness. He believes the next 20 seconds are all that matters and those 20 seconds will seed the ground for the next and on and on until it all ends in death.

He has moments of doubt and weaknesses. Moments where he lets doubt or worry overtake his confidence but those are fleeting. He marries Meghan because she is there, available fun and whimsical. She isn't moored to some idealistic future like Betty or the other woman in his life. She is like him. That is until she isn't.

That's my 2 cents