if only 6% is on exchanges why do HWW makers say 'most people' keep their bitcoin on exchanges?

I listened to the Ledger CEO interview with Odell and NVK and it seemed to be implied only a small percentage of total population of bitcoin hodlers use HWW.

did I hear wrong, the two can't both be true, can they? that everyone uses custodians /and/ volume on exchanges is small fraction of total supply