Utxos <1m may also be combined when forming a txn and one can combine dust outputs together if they all belong to one entity if possible.
Why so much myth about” will be economically unviable”. 
Just like I can combine a penny with a dime or a quarter and then add that sum and spend it. I can do the same with utxo and  burn some of that dust on miner fees. Or use that utxo dust as a Payjoin when receiving.