We work with daily prices, which can be influenced by various factors such as purchasing conditions, stock levels and supply and demand. It is therefore difficult to compare us directly with the competition, especially abroad.
You can find more information here: https://www.galaxus.ch/de/page/dynamische-preise-bei-galaxus-erklaert-39120
Not even the f2.8 version of the 70-200 is compatible with the extender. Canon has pulled a real boner here. However, the f4 70-200s are not compatible with the TCs of other manufacturers either.
Canon is currently offering a cashback promotion for the purchase of a camera + lens (not a kit lens).
Called EOS + X (https://de.canon.ch/lens-promo/)