The case was that Apple lost a billion dollars in sales
They would have to lose a billion dollars in profit, not sales.
it is very unlikely people are suing the companies for such large amounts solely because of what they have been valued
One of the first things a lawyer considers in a case like this is how much money the defendant has. Years ago I was constructively dismissed by a small company which I suspected had cashflow problems. My solicitor advised against suing because it would almost certainly bring the company down, and advised me to sit tight. They ended up paying me more than I would have got in a settlement because they needed me to do some work for them as a contractor.
If a lawyer is told a company is unpopular with a lot of people and is worth billions, he or she may well decide it's worth bringing a case and pushing for maximum damages.
In your case, was the case brought by the neighbor or an insurance company? And what's the maximum third party liability on your home insurance? Because that's the calculation they may have done.