I think they realize that most orgs that are creating a lot of records will share credentials to reduce cost, so they need multiple tier limits to upsell. I’m okay with this because we share an Airtable login. :)
I don’t know. They have some features that use authorship, but if enough people use a custom select column to handle assignments, etc, I could see them making login share more difficult. In a large enough organization, login share is impossible to maintain because of the need for access control.