I would be far easier to do it that way. Congress could abolish or more likely radically reduce the tax code and the IRS, and do it with simple majorities, not blocked by any 2/3rds votes, since the constitution is clear that tax law is strictly majority vote.
To start with, packing the House Ways and Means committee, that writes tax law, with conservatives. At the same time, its counterpart, the Senate Finance Committee, would take the ball from the House. They could even do some extra cutting and adjustments in the conference committee, before an up or down vote in both houses and off to the president.
This is a whole lot easier than changing the constitution.