Removing cap on income subject to SS tax/making SS benefits nontaxable -- Impact?

One method that has been discussed for making Social Security solvent (or at least more solvent) is to remove the cap on income that’s subject to Social Security tax. (I admit this strikes me as a really good idea.)

I suspect that the main reason for not doing this is that Social Security benefits are capped. Therefore, not capping income is unfair to the better off.

But people who make enough that not all of their income is subject to Social Security tax should be in the position of having sufficient assets on retirement that Social Security benefits aren’t the majority of their income. Therefore, their Social Security benefits are taxed (up to 85% IIRC).

What if we no longer taxed Social Security benefits even for high income households? What if we reduced the percentage that are taxable? Wouldn’t this mitigate in part the “unfairness” of capping benefits but not the underlying tax?

What would the net impact on tax revenue be? That is, would the additional amount taxed for Social Security outweigh the revenue seen from taxing SS benefits?

To save you from maybe having to look this up, the maximum income subject to Social Security tax for 2017 is $127,500. The maximum benefit paid in 2017 for someone who waited until full retirement age (66) to claim benefits is $2,687/month or $32,244/year.