I don't think so she was not a previous monarch like her Uncle.
Noel Botham in his book, Margaret: The Last Real Princess, quotes Captain Townsend’s reasons as to why the couple never married.
He is reported to have said: “She could have married me only if she’d been prepared to give up everything - her position, her prestige, her privy purse.
“I simply hadn’t the weight, I knew it, to counterbalance all she would have lost.
But it seems Captain Townsend didn’t resent Margaret for her decision not to marry him.
He added: “Thinking of it calmly, all these years after, you couldn’t have expected her to become an ordinary housewife overnight, could you?“And to be fair, I wouldn’t have wanted that for her. Let’s say I just knew that, if she gave up everything, it wouldn’t work out.”
I think the Queen Mother's views would also have been a factor.