I recently watched an episode of a US TV series in which almost everybody lit up a cigarette at every opportunity. That seemed strange since less than 16% of Americans now smoke tobacco.
I suspect we see so many on-screen smokers because the tobacco industry is paying for product placements. Presumably they are spending their money because they think on-screen smokers make smoking look cool and to persuade the young and gullible to take up this stupid, expensive and very dangerous habit.
The UK has effective legislation on tobacco advertising. These product placements are subverting that legislation.
There is not much that the British government can do to stop this product placement in the US. What it could do is stop smoking scenes being shown in the UK by insisting on the deletion of such scenes from any production being shown in UK cinemas or on UK television. The BBC could take the lead by adopting this policy now, without waiting for government action. [The government might be slow to act because it would have to ask for permission from the US
If a no on-screen smoking policy was in place many US productions could not be shown here. US producers would then have to weigh the money they get from product placement against the loss of UK revenue.