> losses due to inflation nor losses due to risk, both of which are substantial for capital income but non-existent for wage income.

Neither is true.

The only asset class directly hit by inflation is cash. No high net worth person in their right mind holds substantial cash for a longer period of time. If they do, it's a conscious choice and it's not clear why the tax system should help in that situation.

The risk of a wage earner is to lose their employment because the business folds. Just like the shareholder in that business. It's again unclear why the tax system should compensate both differently for this.