Actually, the last data set was missing about 1000 ILS approaches worldwide. And a lot of the stock data is inaccurate.
You’re correct that the stock avionics don’t use the whole data set provided, and a lot gets filtered out and discarded for whatever reason. The WT team analysis was right. The data is a lot better than what we would believe using it in the sim. It’s still incomplete and has a lot of inaccuracies. Although that’s improved with every cycle so far. The first couple of cycles, it had at best 50% of the waypoints, approaches, etc. Last month’s data was the most complete so far.
One g;aring error I notice is that my local airport is an untowered / uncontrolled field with the stock data, and only has a single ILS and a single RNAV approach. In reality, it’s controlled, has 1 ILS and 3 RNAV approaches. Navigraph data fixes that for me. And the radio frequencies in stock data don’t match real life frequencies, making real charts useless.