To you original question, yes it could be considered a liability but one that appreciates over time vs other liabilities that depreciate. If you had invested in the bay area even 5 years ago in some areas, you would have made a lot of money still and not missed out on the appreciation. I've seen rents go up significantly recently in the bay area so in some cases it would have been better to buy vs having to had increasing rents. With new laws for renters, maybe that'll be different.
Rents have gone up but i've had friends who's landlords have been nice and not increased their rents much because they are good tenants (maybe difficult to find and landlord like that). We have been pretty good with one of our tenants not increasing their rent much over the past 7 years since they always pay rent on time and never have issues. If you have this situation, then I would say invest in more assets.
My neighbor bought their house and rented it out right away which actually covered PITI completely. They didn't move in until a couple years because it was just 2 of them and they didn't need a 5 bedroom house until they would have a family so they lived in a small condo. Later when they moved in they still rented out the in law suite for $1500 a month which covered a big chunk of the mortgage. So they had a lower price point, lower mortgage/property tax and all that before moving in 2 years later when it had appreciated 30%. They did well to buy their future property as a rental.
I think everyone is different in terms of wanting to own their home or rent and invest. It could go well either way and their are successful people here that have bought their own homes before renting out and others who have rented and invested wisely. I've seen plenty of people rent and buy fancy cars and DJing equipment so it really comes down to mindset.