The problem is that too many "dummies" have gotten a hold of the higher powered portable chargers and fried 12 volt equipment still being used on the 12 volt circuits while trying to use the charger. They forgot to make sure the battery(s) were disconnected from the 12 volt circuits.
After being sued a few times for damage being done by their charger from miss-use by some fool, the legal department comes into play and all the higher powered chargers (i.e. 40 or more amps) disappear from the market.
Moral of the story. Those of us who can correctly use one can no longer find a replacement if needed. We represent a very small percentage of total sales for all size chargers so we can be ignored with no consequence for the manufacturer for dropping the model.
That's life in the fast lane now days.