The answer has to be to grow the economy, increase productivity, reduce the number of unemployed and part timers (those who "could" work more), to get the economy going again.
We can't keep increasing taxes on the same group of people, i.e. workers, as they're the people we need on board to keep working both for tax revenues and producing the stuff we need/providing the services we need.
Let's forget about tax for the time being and put all efforts into getting people working, i.e. better education/skills training for the young, reduced incentives for the old to retire early, more incentives to get part timers working more, and both carrot and stick to get the feckless and idle doing something productive.