As long as the airplane crosses the threshold at the CORRECT speed and path and with an APPROPRIATE power setting, then we can all affirm that the flight has been conducted in a safe manner.
Somewhat simplistic - many have achieved this following an unstable approach.
The heart of the stable approach is the concept that repeatedly performing the same task makes the pilot ever safer in performing the stable approach, eliminating the risk - however good one is - that a gross error results.
Heightening stability of the approach, resulting in ever more precise landings would probably save more fuel across the fleet as a whole, than permitting deviations from those procedures that with the slightly less capable pilot will occasionally result in a go-around. Furthermore, you eliminate the chance of the one-off gross error by a huge factor.
As ruibk very correctly points out, we live in a safer era than ever before - even still, the vast majority of disasters are human-error induced. It amazes me that some people think they are better than the collective body of knowledge accumulated over 100 years of experience.