Would be the financial implications of a majority of the population opting out of spam snail mail? Service in major metropolis would continue, but what about the cost for small towns and rural areas?
With all the security concerns going around these days, I would imagine that it is not that far-fetched to get all spam-mail as opt-out, at least. That way, you could control who sends you what.
But remember that the Government will always be the government – You need a physical address for an amazing amount of transactions and procedures.
And the Victoria Secret catalog is simply easier to browse in its physical form.