Why removing County-class high elevation saves little

Would County-class cruisers be better without high-elevation capability for the main battery?

No; the saving would be slight, and the simplified Mark II mounting proved worse rather than lighter and better.

The expected saving is small, and historical attempts to simplify the mounting did not produce a clearly lighter or better turret. The Mark II installation used in York, Exeter, and later Counties warns that deleting capability can create a worse mechanism rather than useful design margin.