The most consistent long-term indicator of where a team will finish in the league, is the wage bill. The teams with the highest wages, finish higher. Season-to-season there are the odd blips, but over time, teams regress to their position in the wage bill table.
Our wages bill has been 7th for the last couple of years (unless it's changed recently?). So finishing higher than 7th, is, in my opinion 'overperforming'. There will come a time when our finances have improved such that our wages are comparable with the top 4, and then we can 'expect' Champions League and title challenges each season - but right now, Unai is doing more with the players at his disposal, than would ordinarily be expected.
Which to me, shows that he is an elite manager, and he is CAPABLE of getting better performance out of the players at his disposal. That's not true of all managers.