I have mentioned before that so called full range speakers really are not! The salesman claims: "Sir with these full rangers you will never need subs"
This is, in it's most innocent form, a misunderstanding or ignorance but probably a simple lie.
Get those full range jobs home and position them for good sound stage and imaging and have compromised bass as has been mentioned earlier in the thread. To set them up for their bass potential would then ruin their imaging qualities. Result is dissatisfaction and money wasted. Those expensive jobs will work but need subs.
Many times, and I can't think of any right now, some high-end speaker manufacturers have a model or two below their 'full range" flagship speakers that use the identical mid range and tweeters, which they boast of, in a smaller cabinet with smaller woofers and the considerable $$$ saved will comfortably buy 2 good subs to augment the bass and if properly positioned and set up will handily outperform the flagship imposters 😜