As much as I'd love 220 to make a comeback I'm not willing to see it happen at the expense of the financial health of a film-producing company. Better to have rollfilm in 120 for a long time than 120 and 220 for only a couple of years before both disappear. When companies like Ilford will no longer produce different coloured caps on their film cannisters because the volumes and cost required is not viable then I think there's little incentive for companies to bring back 220 in a declining market (albeit one whose numbers may stabilize in the future).
How many of you who could get a film in 220 that you like would refuse to shoot the 120 equivalent if the 220 version disappeared? Very few I suspect. How many of you would switch from one film in 120 which you regularly used and liked to a different film in 220 simply because it is made in 220? Again very few. These are probably two major questions that companies would examine in a decision to reintroduce 220.
I haven't timed myself but it can't take more than 30-60 seconds to change a roll of 120 in my Mamiya 7. Those who think that is too long (usually commercial shooters) will probably already have made provisions for their shooting like multiple backs, multiple cameras and assistants.
220 - nice to have but not at the expense of having nothing in the near future.