Should Biden limit taxes increase to those making more than $400k?

Biden recently announced that no one earning less than $400,000 would see their taxes go up, and this approximately corresponds with people in the top 1%.  Given the incredible stakes of the election, this cutoff makes sense politically, especially since one of the swing constituencies this year is the relatively high income people living in the suburbs.  Reassuring those people that their taxes won't go up will help win those votes.

Targeting tax increase to the top 1% also makes sense for trying to solve the income inequality problem.  The share of income going to the top 1% rose from 10% of GDP to 20% of GDP, so clawing some of that back through higher taxes makes a lot of sense.  Given that Biden is a moderate and has some plans for new spending, but not exorbitantly costly plans, limiting tax increases on the top 1% should be more than enough, and could easily raise taxes worth 1% to 2% of GDP.  

Long term, however, this income threshold for tax increases is far too high.  At some point, I would like to get rid of some more of the itemized deductions still left in the tax code, and raise the income cap on the payroll tax for Social Security.  This would generally impact only the top 10%, which still protects a lot of potential voters, and targets the tax increases to those doing relatively well in this economy.  

Eventually, if you want to do a lot more spending, you do start to run out of money by limiting taxes on the top 1%.  Once we get the tax levels on the top 1% to the place we want them, I would propose a grand bargain, where Republicans let Congress enact a new Value Added Tax (at say a rate of 6%) and then the Democrats allow Congress to repeal the payroll taxes used to fund health care, plus the extra tax on investment income enacted along with Obamacare, while keeping the payroll taxes funding Social Security untouched.  This would give a tax break to the rich in a variety of ways, and would allow Democrats to raise an extra $100 billion a year or so to spend however they want.  This would move us closer to the grand bargain often used in Europe, where governments do enact generous expansions of the social safety net, but usually use broad based tax increases like a Value Added Tax to pay for it.

So Biden's plans are just fine for now, and do make sense in this difficult political environment, but down the road, I think we do need to look at other options for raising taxes, and I do worry a little bit about setting the precedent that only the top 1% should pay higher taxes long term.