There are different ways of looking at it, but u could invest the 20K and get 6%, so that is lost income.
I dont see property doubling in the next 10 yeras, wages growth plus interest rate rises simply cant justify it. If anything it could be a decade of no growth, or very minimal,
population is also more transient nowadays, and dont tend to stay in 1 place, and the buying and selling costs, bank fees will eat any increase in the next few years imo
so the person renting and saving 8k a year, will be in a better position in 3yrs than the person buying imo