France manages a reasonable standard of living at 4.5T/capita/year (albeit with a LOT of nuclear, which may be politically and economically difficult to reproduce elsewhere). EU as a whole is 6.3T. So not really an order of magnitude, necessarily. The US is an outlier, granted, but mostly for fixable reasons (in particular, over dependence on cars due to poor public transport).

2T/capita is extremely ambitious, but not inconceivable.

EDIT: By the way, it is notable that even before climate was a concern, CO2 emissions in developed countries were largely falling, since the 70s. This was a result of the oil crisis and other energy security issues pushing greater efficiency, plus the replacement of coal with gas for air quality and economic reasons.