Laidbak,
Unfortunately, I don't know of any hard data to support your position, although it may exist. I do know that I don't feel completely proficient after a week off, nevermind a few months.
Beancounters & many managers tend to take a very short-term view of economics. They only look a quarter ahead at most in many cases, & take the position "We won't spend money if we don't fly, & probably nobody will crash anyway. We'll worry about that next quarter". In reality, one accident will cost more than all the training flying you would do. The cost may be immediate, or more slowly in the form of higher insurance premiums & less business, but it will surely come. How to convince ignorant managers of this is the $64,000 question.
Heedm,
IME, pilots trying to do any form of marketing is a sure way to get into the doghouse. In my company, many pilots have tried to point the marketing gurus to business, only to be told brusquely that their interference wasn't needed. And in Florida out of season, there just isn't much business to be had, period. It may be different up in the Great White North.