Yes they did. To amend the powers and limitations on the federal government not the states. The Constitution, or the limitations therein, was not intended to apply to the states except in very specific instances
Please show that qualification in the Constitution. After all, the Constitution itself both grants powers to the fedgov and places limitations on the states, among other things. Amending the Constitution to enlarge federal power if 3/4s of the states agree is hardly out of line with how the document is crafted.
Article V The Congress, whenever two thirds of both houses shall deem it necessary, shall propose amendments to this Constitution, or, on the application of the legislatures of two thirds of the several states, shall call a convention for proposing amendments, which, in either case, shall be valid to all intents and purposes, as part of this Constitution, when ratified by the legislatures of three fourths of the several states, or by conventions in three fourths thereof, as the one or the other mode of ratification may be proposed by the Congress; provided that no amendment which may be made prior to the year one thousand eight hundred and eight shall in any manner affect the first and fourth clauses in the ninth section of the first article; and that no state, without its consent, shall be deprived of its equal suffrage in the Senate.
Funny, I do not see any mention that amendments can only limit the power of the federal government.
Maybe you're one of those folks who have extra-special vision that can see penumbras that others cannot.