Fundamentally, there are four main responses to the Fermi paradox:
1. We really are the first.
2. Interstellar communication and travel is effectively impossible.
3. Interstellar communication and travel is possible, but is not executed in a sustained way for various cultural reasons.
4. Alien life exists, but we haven't or can't find it.
All of those explanations are very plausible answers. In fact, the notion that we "ought" to have found alien life by now is itself quite difficult to argue, because it relies on extrapolating estimates from 0 data points (note that we don't know how to become an interstellar species, and it's debatable if we even yet have the technological level to become an interplanetary one).
1. We really are the first.
2. Interstellar communication and travel is effectively impossible.
3. Interstellar communication and travel is possible, but is not executed in a sustained way for various cultural reasons.
4. Alien life exists, but we haven't or can't find it.
All of those explanations are very plausible answers. In fact, the notion that we "ought" to have found alien life by now is itself quite difficult to argue, because it relies on extrapolating estimates from 0 data points (note that we don't know how to become an interstellar species, and it's debatable if we even yet have the technological level to become an interplanetary one).