“Politicians would not want to reduce their own power.”

The claim is too absolute. Political-science literature explicitly discusses cases where elites voluntarily dilute their own power or precommit to restrain government behavior, because doing so can serve longer-term goals. (sciencedirect.com) In U.S. politics, the Congressional Research Service notes that Members of Congress continue to introduce term-limit amendments, which would directly curb their own future office-holding power. (congress.gov) So it is not true that politicians would not want to reduce their own power; some do support power-limiting reforms, even if self-interest often points the other way. (sciencedirect.com) Sources: Washington University Law Review, "Constitutional Moments, Precommitment, and Fundamental Reform: The Case of Argentina"; ScienceDirect, "Dynamic enfranchisement"; Congressional Research Service (Congress.gov), "Term Limits for Members of Congress: Policy and Legal Overview".