Why not? Under your system of implied powers, we get reems of laws that are passed by the basic legislative requirements. To add an express power would take an amendment, which presents higher hurdles. Look at our tax code! You want reems of paper? Better to make them explicitly acquire each and every power, by super majorities, including the states, then to let them run willy nilly, which is what the system does now.
But you think, somehow, a two thousand page document of fundamental law will not produce reams of laws? Of course, the document would not actually become a two thousand paged document. The trouble of passing all those amendments to permit each activity requiring the “express powers” for every new law would soon have become tiresome. Do you not understand that your voluminous constitution would soon fall prey to the same sort of construction that has befallen our present constitution? And probably in less time than taken with the Constitution.
Can you not see that it is not our constitution that will change the nature of men, but that it is the nature of the men who wrote it that produced our charter? Not perfect men, to be sure, but better men for the most part than the men who have followed. Certainly better than the present crop. We see some hopeful signs that that circumstance may be changing.