tbh, it's probably not economically viable for a company to do it. I remember asking a well known trailer manufacturer decades ago about doing it and I shan't repeat the reply on an open forum!
You can imagine the pain involved in stopping the production run to place an axle in the machine and reverse the huge press to pull it apart and then press new arms in.
Unfortunately, if they're not easily repairable (need to be careful if you weld them, due to heating and ergo softening the rubbers) then a new axle's the only way to go.