You are comparing apples and oranges.
The Polish buff runs out and is supposed to help Poland in a race to defend its borders. MEFO bills gives other bonuses than just consumer goods reduction and is supposed to help Germany ratchet up its military industry. If you as a player are playing Poland I am pretty sure that you "are not just supposed to die".
You cant just take spirit in isolation and compare it to another spirit in isolation. Its like how a 10% recruitable population works very differently depending on a country's manpower pool. You wouldn't say that if the US got a 10% recruitable manpower spirit and Sweden got a 20% recruitable manpower spirit and now suddenly Sweden is OP because of it would you?