You would be wrong. My expenses are quite low compared to most. Some liabilities such as college loans and tax must be paid. But I do not go and create new liabilities for no reason.
It all depends really. If you have enough assets generating enough income then you can support a more expensive lifestyle. So when I say "low" I guess it would be low compared to a lot of other people but not quite where I want to be. So I would say if you can for example not have a credit card, not have a mortgage, not have a car, not waste money on over priced clothes, then yes you're reducing expenses. But the amount of expenses you have to take on depends on what it takes to make you happy individually. So low for me could be high for another and high for me could be low for another.
I guess I do understand your POV now. Since we all are different,then,we can not follow the same investment plan. With different expenses,lifestyle and desires,different plans would fall into place.