Institutions drive the market. Future economic uncertainty around growth and inflation pushes up long term yields, which pushes up the cost of sovereign debt (both new and for refinancing), forcing countries to live within their means from a budget perspective; it also impacts downstream credit product pricing such as mortgages and auto loans. Retail uptake is immaterial (enjoy the juiced yield if you can while you can).

(the total value of the US bond market is estimated at over $55T as of May 2025, making it the largest bond market in the world. As of July 2025, US Treasury securities alone represented over $27.2T of the market; total sovereign debt outstanding as of this comment is ~$100T per the IMF)