Adaptations and fanfiction do tend to exaggerate the economic difference between Darcy and the Bennets to make the romance more dramatic. They also tend to make Elizabeth more progressive and egalitarian than she actually was; in general fanfiction is very prone to exaggeration of characters and situations. However, while the match was not degrading for him, it was a big deal that a rich aristocrat chose the daughters of an insignificant country squire: the stories that show Elizabeth immediately becoming a big hit with Darcy's relatives and the ton in general are equally unreallistic. Also, while we know Darcy's income, we are not given many indications of his actual social position, which had to do with more than money: he might be just another well-off man (his 10,000 pounds were average for his class) or the Darcys might be a powerfull family with great connections and influence.
Charlotte married for security, not wealth. She was 28 years old, plain and with only 500 pounds for dowry; she couldn't afford to turn down any respectable offers, as it was unlikely that she would get another chance. I dont' believe she would have refused Collins, if Longbourne was a poor estate; she probably would have married him even if he wasn't the heir. Charlotte marrying a vicar with an assured position and a rich patroness was a respectable match for her, while marrying the heir to Longbourne was a brilliant one.
Charlotte married for security, not wealth. She was 28 years old, plain and with only 500 pounds for dowry; she couldn't afford to turn down any respectable offers, as it was unlikely that she would get another chance. I dont' believe she would have refused Collins, if Longbourne was a poor estate; she probably would have married him even if he wasn't the heir. Charlotte marrying a vicar with an assured position and a rich patroness was a respectable match for her, while marrying the heir to Longbourne was a brilliant one.