Refinancing. Real return on invested money

Hi folks
This thought may generate some discussion.
I have long been of the opinion that the quicker I get my money back from an investment means the better the investment whether it be from growth, cash flow or differing degrees of both.
Here is an example:
If I were to invest $100K of my money into a property
that is valued at $500K @ 80% LVR
7.5%pa I/O loan
Coupled with a historical area growth rate of 10%pa
With a rent of $500pw
And extra holding costs (not including loan repayments) @ 25% of the rent

Would mean in "a perfect world" I would be able to refinance the property at the end of year 4 and take my original investment back (including the aggregated extra holding costs) to go to work somewhere else leaving only the continuing aggregated annual shortfall to be reconciled at the next refinancing opportunity.
Furthermore, although the % rate of return on my invested money is falling as the years go by (37.62%p/a at end of year 1, down to 35.34%p/a at the time of refinance at the end of year 4) the refinanced investment is only the cost of the total borrowed funds plus aggregated future holding costs. Which would send the return on invested funds to a new high around 1745.38%pa at the end of the first year after refinancing (based on 5% return on new property value).I do not include the added equity in the scenario as it is trapped or locked into the investment and is still not accessable unless the property is sold or refinanced at a higher LVR.
This is the way I think in regard to investing in property when the desire to build a sizeable portfolio is the goal.
My emphasis is not so much on the actual return from rent (although it is a critical component needed to balance the holding costs and sustain the investment) but more so, the longer term return of my money through capital growth.