It's all relative. I spent six years at university without ever taking a single taxi and I still consider Uber rides a luxury, because I can also take the bus for a quarter of the price or bike for free.
Also, as the OP mentions, the trap of getting used to nice things is that while you soon stop appreciating them, you will feel their loss quite painfully.
There's a huge difference between a luxury and something that indicates you have achieved a lavish and impressive lifestyle. A cup of coffee at starbucks is a luxury.
Lavish and impressive is also relative. Your original statement about "these things are all rather unimpressive to those that actually have them within reach" is tautological: having a yacht with a helipad is not going to be particularly impressive to anyone else docked next to me in St Tropez, even if it puts all of us in the global 0.01%.
I think there's a subtlety in my point that you're missing. When you can just barely manage a yacht with a helipad, you're impressed with yourself for being that successful. When you can comfortably afford it, you cease to consider it something to boast about.
A joke in poor taste. Melbournians are notorious coffee snobs. As jpatokal said, locals wouldn’t be caught dead in a Starbucks. Basically if the cup is taller than 4 fingers 8-10cm or the ingredients include anything other than coffee, water and milk, or it was made by percolating - then it’s not coffee as far as we’re concerned. It’s either dishwater or a confection of some sort.
It may be a fact that Melbourne has more coffee shops per capita than any other place on earth.
Melbourne is a mecca of coffee snobbery, and most locals wouldn't be caught dead in a Starbucks. (Although you need to try pretty hard even to find one.)
Australia is one of the only markets where Starbucks' global domination strategy failed horribly due to several factors (I'm not an Aussie so I can't explain the cultural differences). IIRC, in 6-7 years, they opened ~100 locations only to close over 60 of them. Aussies tend to deride the chain and Starbucks themselves have pivoted and tend to mostly cater to tourists so as not to go under completely.
Also, as the OP mentions, the trap of getting used to nice things is that while you soon stop appreciating them, you will feel their loss quite painfully.