There's certainly a lot of that mentality which can be quite unhealthy.
However.. 'any job is a proper job and any degree is worthy and so are all careers'.
Just isn't true.
3rd+ generation immigrants with a safety net and a more liberal outlook are happier to let their kids be free. Myself included. In fact I would be thrilled if they went into an artistic profession! I'm very musical, loved literature, drama dance etc. Had I been born in the UK, and had opportunity that's where I would have ended up.
However I will (hopefully!) have a house for my children to come home to if things don't work out. Enough experience to guide them into getting a job unrelated to their degree (indeed, this is easier in the UK), and more importantly some £££ to get them started.
First generation parents however have the experience of hard living. They don't want their kids to struggle, and having worked so hard for their money they're not going to throw it away for kids to chase a dream.
There's also historically been a lot of racism in the arts. You can see it getting better with Asian artists like Simu Liu, Ritu Arya, Anya Chalotra and firms delibrately going for diversity but back then if you didn't fit a certain profile you were unlikely to make it big. Now even 'standard' BBC shows have a multi-ethnic cast.
I don't think parents should force their kids into one of 3 acceptable professions (doctor, lawyer, engineer) but equally they don't need to be 100% supportive of EVERYTHING. If a kid wants something so much they're willing to risk everything, so be it but they shouldn't expect parental funding.