Petrol gets expensive and loses TEL additive, people buy and drive LPG cars. Governments add tax to LPG sales. Effectively a cause, an effect and a reaction.
Petrol and diesel get even more expensive, diesel gets a bad (very deserved) reputation, people buy electric cars effectively powered in Australia 50% by coal (with caveats, YMMV). Governments change registration to get fuel tax equivalent from electric car operators. Not in Australia yet thankfully.
Hang gliding, pretty much free but pick your location carefully
Soaring, dollar a minute but only in VMC
Ballooning, 50c a minute but even more weather dependent
GA, 4 to 6 dollars a minute depending on how fast to want spend your airspeed.
So for the East Coast latte sucking metrosexuals (e.g. me) no I'm sorry in my opinion flying won't get cheaper or more convenient. Wherever happens the governments will kill it with legislation and it is in their interests to do so. Slowly, like watching a frog boil. With Lee Rhiannon as your party chef.
For the rest of the country there are literally piles and piles of under used kit and sport aircraft just waiting for clubs or new owners to discover, fix and fly. Cheaply if not conveniently.
Flying is expensive but it doesn't have to be. It just takes time, creativity and initiative. For example I know one club that recently refurbished a two seat plane just to see what it would be like. Go to the Clifton fly-in to find out more!