I'm surprised no one has mentioned this but one rarely retires in their first house... Grow into your house ie bedsitter to studio to apartment to mansion to farmhouse to beach house.
The scenario as initially mentioned, can be argued from a different perspective.
Capital.
Mortgage should not be necessarily a bad thing if
1. The guy continues courting other investment vehicles (The lesson here being 'Don't put all your eggs in one basket')
2. The guy uses the mortgage as 'Capital' ie buys the apartment, looks for better offers, sells it for a profit, get another (with mortgage+profit) sells it etc etc... Use mortgage money as capital in the real estate business, and make money from it while avoiding paying rent
Doable but tricky.
And all the while, he grows to his dream home. Not retiring to some apartment.