First, as a quibble, what Laffer was talking about was a maximum in the middle, not an equilibrium. But even then, his approach was far too simplistic - and not at all useful for government tax-setting policy for the U.S. economy at any relevant point where we might be.

So no local optimum point, eh? Interesting.

The basic problem with his approach is that while it might be theoretically possible for there to be a point where cutting taxes actually raise revenue, that point is most likely at around the 80-90% range that you alluded to upthread. It's not at any point that does or will exist in the U.S. economy in the real world. At any relevant level of tax rates in the U.S., you get the rather intuitive result that raising tax rates increases revenue and lowering them lowers revenue.

This argument is the basis for why liberals say 'never cut taxes'. The problem is the revenue data doesn't necessarily reflect it depending on the time scales one picks to look.

Blaming the "Bush tax cuts" or the "OBBB" is overly simplistic. For one the Bush tax cuts were two decades ago and any effect they've had has long since washed through the economy. Blaming a tax cut from that far out also absolves Congress and Presidents of both parties from being responsible AT ALL for the fiscal state of the country.

We have structural problems in how we spend money. Merely saying 'tax cuts, bad' removes 99% of the nuance of how the dynamics of the US economy. liberals are stridently opposed to ANY reforms in entitlements and/or government spending practices and therefore their solutions default to 'just tax rich people more' (and never mind anything else).