As mentioned in the first sentence from this section, the very first version of the incentive framework already mentions a 50% reduction in overall emissions on Terra:
The initial amount of ASTRO distributed per block (late last year) was approximately 19 ASTRO. This proposal aims to apply the change mentioned in the Incentive Framework (cut the amount in half to 9.5 ASTRO per block).
Now, I think it’s fair to leave the axlUSDC-LUNA, TPT-axlUSDC and ASTRO-axlUSDC emissions unchanged. As for the table being arbitrary: the way to be impartial would be to bring all other pools closer to a 0.1 fee:emissions ratio