Basically, the title.

How good with Tatum be when he reach his prime (27-30 yrs old)?

In terms of SF,

I highly doubt he will be in Lebron/Larry Tier of SF. As in no way imo.

But after that, it is not impossible imo.

KD, Dr J Tier. Very improbable but not impossible.

Pippen, Kawhi Tier of SF. I think Tatum have a decent chance of reaching this level.

Tatum just scored 51 pts in a closeout game 7 of a playoff round last season. He was able to lead Celtics to multiple Conference Finals. Tatum have a lot of 20,30, and even few 40 pt games in his resume already.

How good will he be in 3-4 years?

If he pan out to be just in Pierce, Tmac tier. Will that be a disappointment?