There are pretty much only 2 companies that have really viable subscription on demand services - Netflix (by a country mile) and Disney+.
Netflix manages by having a huge global subscriber base - it is aggressively commercial in the type of content it offers, and makes the most of being able to deliver that content to people in multiple territories. Even then it still has a lot of people on ad tiers. It is also carrying a few billion dollars of debt. It is a Goliath that dwarfs the BBC.
Then you have Disney/Hulu, which only became profitable recently - and is way less profitable than Netflix. That is even taking into account that Disney is possibly the worlds best known (and trusted) entertainment brand, and has the resources to control Marvel and Star Wars in addition to its own huge catalogue of content.
After those 2 you get down to services like Warner Bros. Discovery which I think just about edged into profitability (although they add in their Pay TV revenues to make themselves look more profitable so take that with a pinch of salt). In a similar category you have Paramount.
These are the absolute giants of US entertainment - almost all struggling and failing to make money out of streaming in spite of huge catalogues of globally recognised content and vast resources to throw at these services.
Against this backdrop you have some people saying the BBC should just become a subscription service, in other words it should compete with the US giants and make a profit. Presumably it would have to do this whilst also fulfilling a public service remind - to inform, educate and entertain, providing national and international news, political coverage, schools programming, educational resources, radio programmes, the World Service etc etc.
If US media giants purely motivated by producing content that people will want to pay for still (mostly) can’t make subscription video on demand work as a paying business, I’m not sure how anyone could expect a UK focused public service broadcaster to somehow beat them at their own game!
The licence fee model needs updating, but we need to be realistic. The BBC can only exist as a UK asset if it has a large element of its funding protected. We can’t pretend it could survive as a purely commercial service because everything we know about the market tells us that is all but impossible.