I am willing to pay something in the region of 10 € for the sake of a decent meal like the ones in the 90's.
I expect given economies of scale, you're probably not far off in terms additional cost to improve quality.
I certainly suspect the current target price point given to the caterers by the airlines is far below 10EUR.... at least certainly for Economy and Business, they might stretch a little more for First, but not much. Catering is another expense for the airlines, but unlike stuff like fuel its easier to beat down your suppliers for cost savings on food.
