This isn't true.
At all.
IB HLs go into more depth than A Level. Not only do we go into more depth in class, but we also have to read massively around our subjects. I mean, ffs, in English we study FIFTEEN texts word for word, consider contextually etc. In A-Level you do four I believe. In history I have to know pretty much everything that happened in the world during the 20th Century. Not modular things like A-Level. We do literature in French as well as speaking, listening and reading papers. I do SL geography and my teacher said that she thinks the IB course goes into more depth than A Level. I can't really talk for sciences, as I'm humanities.
As well as this, we have to do CAS, TOK and the EE. Offers are basically "hai, pls get A*A*AAA and do 150 hours of extracurriculars and two extra essays thnx" (this is Cambridge - offer of 41 points with 776 at HL, but A*AA for same course).