The way you pay is the way you perform... Rewarding performance based on KPIs is outcome-based - it has a place, but is it sustainable? Wouldn't rewarding the right behaviours facilitate an environment of enjoyment and innovation - ie where people want to do the best job for their clients for the long term?
Among behavioural economists there's now more interest encouraging "intrinsic" motivation - you do a good job because it makes you feel good. You're good at what you do and you enjoy doing it. You like knowing you've done a lot to help your customers. The way to foster intrinsic motivation is to treat your staff well, of course, but the key is to give people discretion in the way they do their jobs. It's the opposite of trying to tie them up with KPIs.