Don't worry. In the Valley, people from MIT don't have a good reputation as great programmers. For some reason, their education is a lot of 'theory' and less practice.
Apart from Standford\Caltech, Some of the best schools that produce great programmers are your average state school.
I have a theory behind this, which may be correct. Learning to be a great programmer takes years, and school is just the start. People that do well enough go to something like MIT, think they are already very smart, and don't try hard when they come out.
But if you are hungry, and smart, and just happen to go to your average state school, you probably will do better, as you probably are humbler to begin with.
It seems when the rubber meets the street, in startups, building products, that's where the great programmers are made, and lisp is not a requirement to know to be a great programmer, or actually build great products. Having an idea of what functional languages are is a must, knowing them is not.