For simplicity, let's assuming that steem isn't appreciating in value. Under these conditions steem inflates primarily through interest paid on SP, which means the real value for SP holders doens't change since they are all having their SP inflated at a similar rate. I get this part.

The part I don't understand is this...

Doesn't the steem that is used to back SBD need to be inflated at a similar rate to keep SBD from losing value?