Another theoretical exercise on Property Calculations -- is it good for financial gains now?

In recent times, there are many ads on Facebook, on property forums, on developer residential condo launches, how one can profit from buying properties, or specifically, ECs, and have it as an asset in which you could cash in to retire. Specifically, sell and downgrade to a HDB and retrieve cash for retirement.

The question is, in terms of financials, is this really a much better move?

So I decided to do a theoretical exercise on how this really works out. As there are multiple variables involved for different people over different time period, I decided that since this is my blog, I shall take myself as an example, on my own scenario 7 years ago and how it may pan out. Specifically, back to HDB vs Esparina condo again. 

To simplify matters, I will set some variables for my theoretical exercise. 

Starting amount for property = $160k. That was approximately the amount we put into HDB from our CPF at that time, in addition to the renovation we did for the HDB back then. This excludes additional furniture and electrical appliances.

Target timeline: 30 years later. That's the typical bank loan time, plus I would have been 61 years old by then. I highly doubt I will like to go through the hassle of moving house around 70 years old, so I think 30 years timeline should be good. 

Assumed average interest rate over 30 years: 2.5%

I am taking the CPF OA floor interest rate here as a comparison.