I was surprised to be taken quite so literally, but my basic point is that losing 3-4 million viewers in the UK means next to nothing in the context of the global viewership.
The viewers in the UK are worth several times more than any in the rest of the world. It's the size of the UK market and the sponsorship of the team reflects it. Vodafone, Glaxo Smithkline...... Even for foreign car companies the UK market is always the primary one for a sponsor.
On top of that what happens to UK TV coverage is important for everyone else because that coverage gets resold. The BBC coverage is watched all over the world, not just in the UK. Restricting coverage is not good for Formula 1. Sponsors need exposure.
You're being pretty simplistic and not looking at the wider implications.
if Bernie can get China and India watching
They're not though. Everyone seems to look at India and China as huge promised lands but they are not. The vast majority of their populations live in poverty, don't care about Formula 1 and that is reflected in the declining crowds we see turning up to these new world races. Most are getting into financial trouble now the government cash has gone. The heartland of Formula 1 is Europe and the UK in particular. If you lose that then interest evaporates.
In addition, anyone who thinks China is just going to let Western companies in is gravely mistaken. They want things for themselves.
Do Mercedes or Renault need more market share in the UK?
They need to keep it. There is a reason why the UK is called treasure island and why most sponsors in Formula 1 have their main market in the UK. Until that changes it's all just speculation with no foundation.