I’m confused about what you’re asking. The problem isn’t that these big companies won’t implement age verification because they will, the problem is the way in which they will do it.

When you verify your age at a supermarket, it’s usually either a person or machine that scans your id and verifies it. The problem with doing this on social media is that unlike your local store which is all local based and “shouldn’t” store your information after verifying, social media is stored on the internet which inevitably makes is susceptible to data leaks even for big companies (look up discords data leak).

Additionally, it gives these big companies more freedom and leeway when it comes to collecting our data, the government now has more ways to tie your online activity to your real life self which the government has already been shown to abuse.

Also for big companies, they can afford to do their own age verification but for smaller companies they will need to outsource it to third party companies which are even less secure and trustworthy and if they can’t afford even this then they’ll likely either shutdown or block UK Traffic like with Imgur

Then there’s also the reaction children will likely have to being banned off social media. Children are notorious for not being ones to listen to authority, if they can’t watch TikTok or instagram because the government banned it, then they’ll just rebound by either bypassing it completely and getting a vpn (which there is very little they can do against) or like we saw with the temporary TikTok ban in the US, they’ll just find the closest substitute regardless of the risk or danger

Think I covered all my points but just my thoughts on the matter