This time and time again. Income does not equal wealth. Sure over time you can build your wealth and become rich, but not really if you earn £150k.
It takes awful lot of work to get to that level. You are probably be in your 30s or 40s when you start making this much. If you come from working class, then you are unlikely going to have any sizeable assets until then.
£150k gets you "only" £7.5k net. If you want to actually enjoy life and fruits of your hard work, then you don't want to live in a flat share, you want to go out sometimes etc. In London, £3-4k rent for a decent home, nothing luxurious is a normal price. Bills, other outgoings probably £1-2k. You also want to save some money for retirement. With that kind of money, you are realistically looking at £2k of disposable income. To put that into perspective - if you put £2k each month into your savings account, it would take you about 40 years to save your first million.
This salary is really nowhere near making someone rich.
People are often confused, because they see an actual rich person that is making this much money, but they are not rich because they have such a job. They most likely inherited their wealth or they get money in other ways.