65 goals was a crazy outlier hot season for Ovechkin. His 2nd best season was 56G. He averages 50G/82GP.
If current Laine had similar crazy season compared to his career average per 82, he'd end up at 57G. It's unlikely Laine is at his prime yet, I mean his current average is based on ages Ovechkin wasn't yet playing in NHL. Assuming he's at his prime already, 55-60G in a crazy season should be possible, but you can't count on a crazy season like that ever happening.
If you start projecting, depending on how much better scorer a prime Laine will be compared to rookie+sophomore Laine, who knows what he could do in a crazy season like Ovechkin's 65. Assuming scoring league wide doesn't change much, and significant but not crazy improvement from Laine into his prime, 65 or even 70 doesn't seem crazy at all, but to reach those kinds of numbers ever, he'd basically have to be around 50-55G / 82GP player on average in his prime and have a season where everything comes together for a crazy 82 game stretch.
I wouldn't bet on 65 let alone 70 ever happening, but I wouldn't bet against it either. Especially not my balls, I like them way too much.