I can't quite recall the Davion player's reason at the time, that was 10 years ago. It did make sense at the time though.
As the player for House Davion, IIRC, for the AFFS, it's because there wasn't enough Star League technology available to them yet. It's enormously expensive to upgrade and the costs under the rules we gamed meant that I didn't have enough funds to tool up and meet all the other options. The Davion Guards do have most of the available lostech units - only two commands outside of them have any.
I downloaded the CCAF manual and, it doesn't come back with what was stated. Apart from the fact that in 10 years the data can be updated, but there is a great inconsistency with what you have reported.
According to the AFFS manual, there are the names of 100 House units, and of these, only 6 have Star League technology.
In the LCAF manual for the 75 house units, there are only 8 that have Star League technology.
While in the CCAF manual compared to 77 House units, as many as 23 have Star League technology.
At this point there is a percentage of Star League technology broken down as follows:
AFFS 6%
LCAF 10.67%
CCAF 29.87%
The Capellan Confederation's budget can't compete with that of the other two nations, so it couldn't afford to have all those units equipped with Star League technology.
The summary of the data of the countries in KU_02_Inner_Sphere_Supplement_3032_Final contains a gross error regarding the Gross Domestic Product. It is expressed in billions of credits, but it should be more correctly expressed in trillions or even quadrillions. Because even if we multiply the reported values by 7 (i.e. the conversion between Comstar credits and the dollar) they would have roughly the same GDP as Earth, even if they actually have hundreds of planets.