I wish I was zoche to be able to live the kollel life, but personally I felt I needed to provide a certain level of gashmius for my family. However, I know plenty of avrechem and their families who are moser nefesh to live the kollel life. They chose certain areas of life to be uncomfortable in, in order to do avodas Hashem.
Sure there are people in Kollel who have both worlds, they did not have the same nisayon that I had. But to say only the rich are in kollel is a gross mistake. Perhaps rich in ruchnius.
You don’t have to be rich to be in Kollel, only somech b’chelko