We use plenty of cloud stuff, I guess that wasn't clear from my initial comment. We use Office 365 & teams for our 'business' teams, Slack for tech teams & Monday.com for our 'Jira'. The business has evolved from on prem exchange so its natural a trust in MS is embedded.
I wanted notion to get out of document hell. Legacy business with many spreadsheets and word documents. With notion it wasn't the cloud being the issue, we run all in house software & DBs in AWS.
But some startup from San Fransisco offering a platform with notable downtime / performance issues and no direct ownership of DBs was an issue for something like a wiki where you want to be able to publish sensitive information, ip etc. We're in a regulated industry so compliance & security input is ultra relevant.
Sharepoint is a fucking abomination, it's what was previously used. Notion makes a perfect wiki solution.
If it had a self hosted option we'd have adopted it. It was turned down, and fairly so, by our ops team for the hosting situation. There's no reason for something as *simple* as a wiki should be completely outsourced. Portability is a factor too.
We chose wikiJS in the end. Great wiki but terrible writing experience. Tend to write everything in an external markdown editor and just copy it in.
In my experience, you will find this kind of org uses Office365/Outlook, and not Gsuite/Gmail, as they have in place a commercial agreement with Microsoft which covers regulatory requirements put upon them (and some they put upon themselves).
Of course they could _try_ to get an agreeable contract in place with Google, but Microsoft is Enterprise-friendly and can make this happen much more readily.
Single reason we didn't adopt notion is lack of ability to self host.