You can check out the rating of teams going to world finals in previous years.

https://codeforces.com/blog/entry/73791

https://codeforces.com/blog/entry/64909

The problem is that certain regions just have too many slots relative to their density of competition programmers.

For example in less competitive regions, a rating of around ~2100 gives you a decent shot at world finals.

But if you were in a region with a lot of other good schools, then even if you had a rating of 3000 you might not even be able to represent your own school, let alone your region. See MIT's result where their top 3 teams dominated their region but their school can still only send at most one team to world finals: https://nena20.kattis.com/standings