Have you actually priced the MX or Grand L lines lately? The L3560 is cheaper than any MX, the L4060 lists for within a couple hundred dollars of the MX4800.
There are tradeoffs to take into account. If you want most HP per Dollar, MX all the way. If you want weight and 3pt lift, the two smaller LXX60s are equal or better than the MX line. The MX has a higher loader capacity. The GLs have nicer ergonomics.
I feel strongly that the smaller Grand Ls are better balanced when it comes to weight/horsepower than the MX line. The larger two MX machines are turbo charged.
There's arguments to be made for both product lines, which is why they both exist.