I don’t believe that cats do sleep ‘so much’. You will see a lot of articles on the Internet saying that cats sleep 16, 18 or 20 or more hours a day. I do not believe that domestic cats are actually sleeping all this time. They might be resting with their eyes closed or snoozing but they will wake up rapidly at the slightest disturbance. Cats do snooze a lot because often they are bored and they have nothing to do if for example they are indoor cats. I would estimate that my cat sleeps for a similar time that I do and that the average human does. In addition he will snooze for several more hours, thus giving the impression that he is sleeping for a very long time. The major reason why cats give the impression that they sleep so much is because they are inactive because food is provided and their owner does not play with them and the environment is not enriched, all of which is detrimental to their wellbeing.
Arguably, cat allowed outside appear to sleep less because they have a reason to be active and are therefore active and not snoozing.
