I’m all for reducing the inequality gap (a lot) but there does need to be one for capitalism to work.

And that is precisely why capitalism should be abolished. Any gap will grow, the only way to stop it is to close it and hold it shut. Any amount of inequality is injustice.

Several decades ago, the top bracket was 90%, which surely reduced inequality without removing the wealth incentive

And then the wealth incentive overcame the tax pressure and reversed it. The wealth incentive is perverse, there is no reason to preserve it.