The $60B figure conflates very different categories of spending.
CPP and EI are contributory programs funded by Albertans themselves. Ottawa only passes it back to them. Alberta will have its own APP, and insurance scheme.
Debt servicing depends on negotiated debt assumption, not a fixed per-capita charge. During the independence negotiations, Canada is required to negotiate in good faith. Considering Alberta has been a net positive contributor for most of the time the debt has been accumulating, I think a good case can be made that we’ve already paid our share. You may think otherwise, but there is our starting position. If Canada doesn’t negotiate in good faith, then we go the other route and tell them to pound sand.
And while an independent Alberta would need institutions in areas like defence, justice, and foreign affairs, most of the others already exist in Alberta, that does not imply Ottawa-scale departments or budgets, and certainly not the drunken sailor spending levels. Once pass-through funds, duplication, and non-replicated programs are stripped out, replacement costs fall closer to a $15B amount, but lets allow it being $30B, which a flat tax would cover while we build up our resource production, infrastructure and investments.
Well, lets say your are right, you’re not, but we can pretend. Say we can’t get rid of PIT. It is aspirational after all. We’d still be able to make it half of what it currently is quite handily and allow lower income people a higher cutoff before they have to pay. Not something that is going to happen in Canada anytime soon, or ever.