I have no hard evidence that they are actually actively seeking a buyout/IPO, but they did complete a Series E last year[0] led by Goldman Sachs and IONIQ Capital. Presumably their numerous investors will be looking for a solid return, either through an acquisition or IPO.
WRT how they might exploit users, it's not really so much that there are specific ways I worry they will exploit users--well, I guess I am specifically worried they will once again hold private repos for ransom until you agree to some abusive new terms. It's perhaps best summarized with an infamous quote about user tracking from GitLab CFO Paul Machle:
> I don’t understand. This should not be an opt in or an opt out. It is a condition of using our product. There is an acceptance of terms and the use of this data should be included in that.
In other words, "Fuck the users, it's our product. Hold their repos for ransom until they agree." Which they in fact did for a short time until the PR blowback became unbearable. This was supposed to apply to self-hosted GitLab EE, too, BTW.
The fact that Paul survived that very public middle finger to users and the security of the product and remains CFO shows that Sytse agrees with his philosophy, even if he isn't as brazen about it. The kind of money Sytse presumably has made and especially stands to make in a successful exit tends to have a peculiar effect on people, so perhaps it's not surprising...
If you continue to use GitLab, be prepared: Make sure you have a replica of all the content (including issues etc.) you might need in the future. You just don't know how or when they're going to screw you over next, but you can be sure it'll happen.
[0]: https://www.crunchbase.com/funding_round/gitlab-com-series-e...