Drafting high is not the easiest way to get better. Many high draft picks do not pan out. Also, with the new lottery rules, there is no guarantee that you'll get a high enough pick anyway. Example, Detroit had, by far, the worst record in the league last year. They picked #5 in the draft. The way to get better is a combination of good draft picks and good trades. Signing top FAs is not a good option generally. Btw, it's not luck if you're good at evaluating talent. Not everyone is.

IF you have very good talent evaluators and an excellent player development program, you can find guys anywhere in the draft that can be developed into stars. Also, if you're good at those things, you can find players that are a great value and get them in trades. You can also find guys that can strengthen your bench.

Ainge has found guys like that for the Jazz already.

He got Markkanen, Sexton, and Kessler in trades.
He got Collins last year for Rudy Gay and a 2nd round pick. Collins is not the Jazz's top player but is a very solid player.
He picked up Dunn who was essentially cast off. He's a solid role player and very good perimeter defender.
All three FRPs from last year look like they'll have a role in the NBA.
He signed Bazley and Lofton at the end of the year to non-guaranteed contracts. They look like they may have potential as role players.
He signed Juzang as a undrafted rookie and they have worked with him. He may have value as a role player.