I wasn’t saying that Sealion wouldn’t happen or that Germany wouldn’t be successful at it. I was saying that depending on what the UK player does, it could be rather hard for Germany, requiring them to use a lot of resources, or it could even be easy, requiring Germany to use less to take London and therefore have more to start out against the Russians.
I have seen games where Germany went for Sealion and the Brits defended so well that while Germany captured London, they used up a lot of ground forces and even lost a lot of their air force in doing it. Also, the naval investment is pretty big too. A carrier and 10-12 transports isn’t cheap and isn’t as likely to help against Russia. Yes, you could use them to amphibious assault Leningrad, but if you lose a lot of land units taking England, you will have to buy that much more to refill those transports. What’s happening on the eastern border during this? It just could be that in taking London, Germany could end up in a sorry state against Russia.
I have also seen games where UK made the wrong choices, like investing too much in Africa or trying to rebuild the fleet, and Germany ends up pulling off a Sealion with only 4 or 5 transports and their air force. In this case, Germany will still have a lot of stuff to throw at Russia and have all of England’s money to boot.
Of course, a lot depends on the roll of the dice. Unless you use low-luck that is.