You are talking end position after x amount of time, in this case 25 years.
Quite simply, if you bought a house with a $300k mortgage after 25 years you would
-have incurred $675k of interets costs paying interest only
but
-the $300k property rising at inflation of 3% would now be worth $629k
So end position would be a loss of $346k (329k cap gain less 675k costs)
However this is assuming no rental return, which isnt realistic. Even $150 a week rent result in $300k over the 25 years, plus any neg gearing/depreciation etc where it all starts to get murky.
But this is all besides the point. Your original example used principle and interest.
So in that example total costs would have been $455k in interest, versus $329 cap gain, plus $300k rent...leaves you around $174k in the black even with the crazy low rent rate I have used...?
