The difference between 3-an-over (the target-below economy-rate for a Test bowler) and 4-an-over (the target-below for ODI one) is small. That between 4-an-over and 7-an-over (the Twenty20 one) is massive. Equally, in Twenty20 a 20-ball 40 is a brilliant score; in ODIs it's an OK one but not particularly good, while in Tests it's (almost certainly) a plain irresponsible one.
I can't see how anyone can't see that Twenty20 is vastly different to ODIs, where ODIs are - relatively - only slightly different to Tests. The difference between 20 and 50 overs is vast, collossal, compared to the difference between 50 and 450 overs. "Economical" means a fairly similar thing in Tests and ODIs; thus, the fact that it means something totally different in Twenty20 means, AFAIC, that it's realistically impossible to be economical in Twenty20. "Good score" is pretty similar in Tests and ODIs; it's completely different in Twenty20.
Individual excellence is minimised in Twenty20, where it's given full expression in both Tests and ODIs. This is, in my book, irrefutable. It's why I fail to understand why anyone is bothered about arguing who's the better Twenty20 bowler between two teams. Sure, if you really care about your team's success (as I don't) you'd want to pick the best of those available to you, but who's best between two different teams seems to me to be a complete irrelevance.