Looking at recent posts, and picking out some points made
On Fri, Jan 1, 2021 at 03:57 AM, Shal Farley wrote:
All those hard-working electrons (and photons).It is a very basic IT/DataProcessing concept that it's all based on bits - storing, changing, copying them - and it's those that drive the costs and benefits of internet/web services - and those are generated - by individual bits - in picocents: but add up to megabucks: and how you charge and account for them, at an additional cost of kilobucks (or less) rather than (unafforadable) gigabucks that is the great business problem of the industry.
Dave Sergeant, in message 27516, I thinks set out where groups.io is, and its problems lie.
And Samuel Murrayy in 27515 sets out payment scheme worthy I think of careful considerstion, as balancing payments considering the different positions of owners who are, or not, prepared  to pay for their groups, and members who just want to benefit from them. Perhaps not an 'industry standard' scheme, but maybe one to set a new standard.
(The addition to this I would suggest is a 'reserved for invitees' categorisation for 'free slots', but this is, essentially, a detail add on to his concept)
 I think a better word to express my thought than 'can' or 'want', that have been used elsewhere.