Haye does not throw combinations or is a busy fighter, by definition of his style his only chance was to hurt Wlad and stop him. He was never going to beat Wlad on points. Being more active, would not increase his punch output or change his style. Haye is a one or two punch power puncher, who then leashes onto his opponent when he has them hurt.
Inactivity is a major issue and a big pet peeve of mine in modern boxing. It stunts fighters growth. I hate it that most fighters only fight twice a year and it's really counterproductive. Most of it has to do with promoters and tv dates but fighters are just not willling to fight more often these days. There's no way a guy should need more then a couple months to prep for a fight. It's no coincidence that fighters like De La Hoya had there best years when they were most active. They train too long which increases the chance of injury and messes up your peaking time.