To my knowledge of recent case:
To record, produce and master a track with a reputable producer is £8-20k.
To get a support slot for a few shows on a label artist tour is £25-150k depending on the artist.
The have a social media campaign is £10-30k per year. Probably a lot more for large scale advertising.
Radio and streaming plug is £15-25k per year depending on reach.
This is not viable to normal people and only those who; have a sponsor, major label backing, connections who can pull favours or family money.
And especially difficult to find the time when working a full time job to pay rent or mortgage.
Also we are getting to the point now where the kids of 80’s and 90’s pop stars are getting a chance. Even if they don’t have talent they have the connections.