If you currently drive a 7 - 7.5 GTi, Dsg a TCR may well be a halo car for you, (less so if you drive a manual gearbox!)
Yes a TCR may cost more to purchase, but you are likely to retain that delta over time as implied desirability of a TCR helps counter the depreciation. You may even find it appreciates slightly, although we may have seen some of that?
You also need to consider not all TCR are equal. some specs are more desirable than others, although dealer trade in quotes may not reflect this, buyers are willing to pay up for the right extras on a rare variant.
You need to take the price difference into consideration, I bought my Ed40 CS nearly 3 years ago and found a car 3 years newer, better equipped with a quarter of the mileage for a price difference I was happy with, having studied price and spec data on various spreadsheets since the Ed40 was announced.
Maybe this is just how I look at it having spent far too long trading financial bond spreads?
One observation I can make is that 3 years on the cost to change to the same car would appear to be quite a bit more than I paid, which can be explained by the general increase in newish second hand cars and in part by the desirability of rarer variants?
I am enthusiastic about my car and prefer to buy privately while the car is still under warranty, this gives me an insight to how the car has been used, which you may not find buying a car from a car supermarket?
Price isn't everything, it's better to have a car you know the history of and are happy with, buying a secondhand car is not without risk or buyer remorse!