Wrong. For most situaions today, there are plenty of apps that "fill your needs". So it comes down to ux. Starting with a shitty ux framework like swing means eventually someone will replace you.
Yes, and you can absolutely tell they are implented in swing. Dont get me wrong, I use these IDEs everyday because they are extremely powerful and good for understanding large codebases, but the UI is NOT their main selling point, sorry. Swing gets the job done, nothing more.