There are many reasons that 120 and 220 were very popular formats for professional photographers but 70mm was not. 70mm was successful for applications that absolutely required a large number of exposures i.e. 70 and had the extensive engineering support necessary to keep it running. Examples are NASA/military/scientific applications and mass portrature.

120/220 is far better suited to satisfy the needs of photographers. Photograpers have an enormous number of variables to deal with when preparing for shoots and making photographs. 70mm adds unneeded complexity. Mechcanically the magazines are not robust. They require a great deal of attention if they are to be reused and daylight loaded. NASA used modified mags that were darkroom loaded by qualified technicians.

120/220 has the advantage of film that is factory spooled in a clean humidity controlled environment that is momentarily exposed to the environment when reaches the exposing film plane. Camera interface and film processing problems are very rare.

70mm has many opportunities for problems unless the equipment and materials are carefully maintained and used.

Bob