A simple modification of support based on an easily proved material change in circumstances isn’t usually that expensive. Lawyers in my area will often do it for a $500 or $750 for the common client when proving income will not be difficult. Even more expensive lawyers usually don’t charge much more than $1,500 for the typical case. It can certainly cost more if calculating and proving income will be difficult and a lot of discovery will be required, but this sort of thing rarely costs what something like a custody battle would cost. It’s pretty straightforward stuff that more often than not is worked out by agreement without the necessity of a contested hearing. I’ve done several of these in the past and they usually don’t require much more than two or three hours work, if that, including the time spent in court. Obviously there are those odd exceptions, but generally these are some of the easiest and least expensive cases in family court. Most of the contested child support modifications I have had have taken less than 30 minutes to try. Judges will often set aside 15 minutes for these.
Usually it isn't expensive for the mother. Not so for the father. Besides that I've never heard of a recent case where a father got his support *lowered* for any reason. Not for being laid off, not for being injured on the job or off, not for getting sick, not for being a victim of a flood, fire or hurricane...not for any reason.
Reason being the judges and CSA's work together. Keeping support orders high enables the state to get more federal kickbacks. The state can spend that money on anything they want to...they don't have to account for the money to anyone. Judges can't by law get kickbacks but they do benefit by receiving higher retirement benefits. You yourself admitted you hadn't practiced family law in a long time. Things have changed.