Having passed my three score years and ten little to nothing of the past feels that far away. I bought my first mobile in 1992. I say bought but you rarely did because they cost then £2000 or $3000 dollars so you rented on a lengthy contract. The phone was the size of a ladies handbag. the battery would hardly last more than a couple of hours of use so I had four. Each battery was the size of a machine gun cartridge. The telephone did one thing: make and receive telephone calls. Today, my mobile slips into my shirt breast pocket and has the facility of a powerful computer. The battery is tiny and will last all day if not two. There is very little it can't do including being a high definition camera and act as a comprehensive GPS; both for aviation and with road moving charts/maps for navigation. For road use the software can be free with apps such as Waze. All this is for a few hundred pounds.
So, for me, 20 - 30 years ahead is no time at all, its if it was tomorrow. Avgas is already struggling to survive as petrol is required less and and in some parts of the world impossible to buy. It may not be the case that Avgas is only expensive then, in the foreseeable future, but it could prove difficult to obtain irrespective of price. Mineral oils already are only available because of the total loss demand of the food processing industry. Oil producers don't see their future in petroleum products. They would stop making avgas and mineral oils tomorrow if they could.
Last edited by Fl1ingfrog; 26th Apr 2022 at 16:47.