I wasn't aware to the fact that they are higher in M&M compared to other *A programs, it doesn't make sense since you can book the flight award in most other *A operators with your M&M miles. Is it still higher? Or do you mean the cost of covering those with miles?
The price of covering taxes with miles in M&M is 18,000 miles. I have no idea how much is it in other programs, but it's hard to believe they offset the milage requirement. For example a flight from TLV to Europe in Y would cost 30K in M&M compared to 40K in other programs. And the same flight in C would cost 45K with M&M compared to 70K on other programs, so even if you pay taxes with miles it would still be cheaper.