I'm in the UK, where things are a little different: our houses are much smaller, our cities are walkable, and most places have fair public transport.
Still, not only is the advice your aunt gives pretty standard around here, but many of the things on the list are the lifestyles of actual millionaires. (The true kind, not just someone who's inherited a house in the suburbs and paid into a pension for a bit.)
It is unreasonable to expect most people to go without Netflix and the occasional Starbucks treat. That's something that almost everyone, at any income level, can expect to enjoy without guilt or judgement.
A mid-senior manager at a mid-sized company in the UK might have one designer handbag, have one European holiday (economy class) and a smaller weekend trip per year, have someone landscape their garden as a one-off contract, and eat out at a restaurant maybe twice each month. They would have a decent used car, a gym membership bought in January and cancelled by April because they forgot to use it, a spa trip for their birthday and a new phone every 3 years and a new computer every 5 or 6 years.
Even on an above-average income, only about half of people have dishwashers and hardly anyone has their own regular cleaner or gardener.
Most people don't either cook from scratch or hire a chef, but assemble pre-prepared ingredients from the supermarket. If you're wealthier, those ingredients will be a little fancier.
The person who flies first class, who outsources all their services, who lives in a large house in a great neighbourhood, who has regular spa days and rarely cooks for themselves is normally the CEO.
The lifestyle your Aunt Kelly disapproves of isn't a regular experience for either the poor or middle classes - almost nobody lives like that. When you read the Guardian newspaper talking about 'middle class' lifestyles much like the ones you describe, it's the one their readers in professional jobs with good salaries might aspire to but seldom get to experience.
And if anyone was sitting in a t-shirt with the heating on here in the UK, someone would ask them why.
