Why does everyone always say that the
price of formula gear is talking them out of it?
I'm pretty sure a 9.8m slalom sail costs the same as a 9.8m formula sail; because they are the same sail. How much does a 130l slalom board cost? Give or take $100 probably the same as a formula board? (don't quote me on that, just in case I stuck my foot in it

). I raced nearly the entire season in NSW with a 75% carbon mast that I'd repaired. There's no reason to see formula sailing as "I can't afford a 100% race-mast and latest 2008 sail; therefore I CANNOT sail formula". Plenty of guys at the front of the fleet have last years sails/boards or 5 year old fins.
Granted. Not too many people sail formula up here in Queensland recreationally, but I see LESS people on larger slalom gear out sailing recreationally. Its starting to change up here however. I see a few more guys out on big gear each year in the light winds and the second hand formula kit around the east coast gets snapped up pretty quickly!
Also, in regards to formula helping/dehabilitating your shortboard skills, I think the key there is TOW. Formula may/may not help you tack an 80l board, but it certainly gets your fitness up (as you will go sailing about 80% more than you would if you only owned an 80l board) so you can concentrate on your tacks/gybes rather than worry about your forearms blowing up or you back going out after not having sailed all winter.
My ballistic-wind slalom sailing has really gotten good after years of only sailing formula. Sailing formula really hones in your reflexes and makes you concentrate on your stance a lot; which definitely translates into shortboard sailing - especially in high-winds! Just remember not to step so far across with your back foot when you gybe!