The article literally gives an example of her cousin (i.e. not a direct descendant of the current monarch) trying to get himself crowned; it's not like she had to have kids in order for the monarchy to have an heir after her. Claiming that the reaction would have been less severe if she promised not to have kids seems pretty baseless.
She was pregnant 15 years after the reluctancy that was described. Can you provide any actual evidence that they were concerned about that specifically? It sounds a lot more like you're making an inference of two arbitrary facts in the article being related, and it's hard not to get that impression it says a lot more about your biases than having any basis in history
