Is Kelly what Joe was prior to leaving Boston? I would contend that he is very close.
Joe Johnson was a 20 year old rookie when he got traded here. His 3rd season was a breakout year and his 4th year, prior to hitting free agency, he played like an all-star.
I would contend that their situations are almost nothing alike.
Kelly Oubre has played 4 years in the NBA and didn't look particularly good until the final half of his 4th season. Half the league had space to give offer him the kind of contract you're talking about and no one came calling, even in the last few days as all the other free agents dried up we saw Dallas and the Lakers ignore him despite both having more than enough cap space and a need for a player of his type.
Oubre would have to make a dramatic leap for him to even sniff the money you're talking about, I'd be fine with 4 years, 60 million, but even that, based on what he has done in his career, is a serious overpay and a gamble that he will make significant improvements.