My notion of Low-Fi would be Denon,CA,Nad,Rotel,Marantz,(up till 8001).
Mid-Fi would be Arcam,Cyrus,Primare,Rega,Creek.Naim too,but at HiFi prices

Hi-Fi would be Bryston,MF,Krell,Jeff Rowland,Accuphase...
Of course top end models of each brand may overlap with the entry level models higher up the ladder.
But all these defintions of Low/Mid/Hi are relative.I seem to remember Prem describing his Esoteric cdp as Mid-Fi in a post!
The words we use and the meaning we impart to these words is considerably coloured by the amount of money we have in our wallet