No. Aluminum is too light, less than half the density of Zamak. Brass or bronze would be the logical choice and it won't ever crumble (although it can develop exterior corrosion in the presence of ammonia vapors.) However- brass locos sold by 3rd Rail and previous two-rail scale manufacturers are soldered together by hand out of sheet brass. This method is fine for low-volume models aimed at adults. It permits thinner walkways, etc., and importantly, avoids the high initial cost of tooling up a mold. Locos made this way wouldn't be durable enough for starter sets aimed at kids.
As the demographics of our hobby decline, the economics of die-casting for mass production are grim. Unless some future technology permits the molds to be rapidly and affordably created through automation, we may NEVER see another new single-purpose mold.* That's sad, because personally I just like the 'feel' of a thick casting better.
*Never say never... Unless I'm mistaken, there were no new die-cast locos developed for O gauge between the Lionel 'J' (in 1957) and the ill-fated Rock Island 4-8-4 (in 1987.) That Rock Island was a new boiler shell on a Berkshire chassis. But it was followed by the all-new Reading T1 in 1989, which opened the gates for all the subsequent new models from Korea and China. One can hope!!
