I'd guess that a lot of the small countries weren't spending it at all.
There's a fairly strict limit to how much power you can sensibly spend on buying technology and ideas. (Buying ADM or DIP technologies with even a single year of ahead-of-time penalty really isn't sensible most of the time, and no equivalent concept even
exists for ideas.)
Once you've done those things, the remaining major uses are:
- ADM: raising stability (but raising stability above +1 by monarch power spending is only a good choice if you've been stacking stability cost bonuses).
- ADM: buying cores (but only if you have uncored provinces)
- ADM: inflation reduction (but only if you have inflation)
- DIP: annexing subjects (but only if you have subjects)
- DIP: reducing war exhaustion (but only if you have WE)
- MIL: strengthening government (but only if you are below max Legitimacy / Republican Tradition / whatever, which small countries frequently aren't)
- MIL: harsh treatment (but only if you have Unrest, which small countries generally don't)
- All three: development.
And thus the conclusion is reached:
The development system is rotten to the core, and the only reason you noticed it's bad is that the AI has had its handcuffs taken off.