Mark has done a fantastic job of coping with the influx of groups from Yahoo! Groups, especially at such short notice. Thank you!
I am concerned, though, that the new prices will drive away a lot of basic groups. I'm co-owner of four related special interest groups (covering sewing machines), each with a lot of subscribers and a long history, but not much traffic. Sewing machines are a hobby, and one on which I spend about $30 per year in total. The prospect of paying a large share of 4 x $220 per year to transfer and run these would have me archive and close the groups, if I couldn't find a new owner prepared to provide financial backing or collect donations.
For such groups, where there is no organisation backing the group (just a few volunteers as group owners and moderators), membership thinly spread around the world, and no momentum or ethical need for the group, just a "nice to have," a fixed fee of more than pocket money will end them. Please work out a pricing system which does not cut in with a substantial cost as soon as a group reaches 500 members, at least for non-profit organisations or informal non-organisation groups.
(In the short term this does not affect me directly, since my groups are older than 22 October 2019.)