I feel like you're implying that the mere act of consumption is good for an economy. It is not and the idea was critiqued 200 years ago by Bastiat in his parable of the broken window.

It's perfectly good for the economy if wealthy people save/invest in production instead of consume themselves.

Pointing out that poorer people have higher MPC simply doesn't mean that redistributive policies would increase production or consumption. It's entirely possible that such policies would decrease overall savings rate which you seem to think would be good, but would reduce total production and consumption.