Damn that's the most fed lokknaar I've ever seen in my life 730 kills holy shit how come she hasn't been vaporised yet (even in a tank)
Implo bomb launcher is a common bottleneck, it's a bomber weapon and they never land and seeing you only have one proper interceptor i'd bet you haven't downed many, if any.
And yes, when a downed ships engines explode it destroys items on its tile so if you're unlucky you can down a few bombers and don't get any parts. I had a run just like that once, I knew what was the bottleneck but the bombers just refused to spawn and after I downed like four and didn't get a single part I ragequit that save.