That just disregards one of the biggest parts of a solve, that is; efficiency. Speedcubing is not just about how many algorithms and how high your TPS is, it is also about how you plan and apply those. Without inspection, you are essentially just winging it. A lot more luck is required and the skill of intuitively planning out further steps is completely removed.The REAL difference if the 15 second allowance was removed is that you do the inspection during the solving (clocked) time. The more skilled Cuber would be able to inspect faster and plan better in less time, in their looks. Anyone can choose to spend more seconds in planning or start turning, but everything is clocked. That is fair and that can show who the better Cuber is than artificially enhanced times like 3.47, 3.79, 4.1.
Anyway, I do see your point and if you are interested with discussing this further, I suggest you post it also on the WCA Forum