Cosmologists would agree with you. They are looking to define the hand waving they have to do in order to explain the universe we can see. Whatever that explanation is, it must be “shaped” like dark matter, though. This is different than epicycles, which were a specific “solution” to the problem of Keplerian motion. Dark matter is not an explanation, it is an observation in search of an explanation.

Here’s a not-so-bold prediction: sometime this century some team will detect something new that explains some but not all of the effects we currently attribute to dark matter. We will call it the explanation to the problem and the remainder will be given a new catchy name and people on the HN of the future will complain that this thing is simple hand waving.