1) Would it be necessary for all MN's in the mixing rounds to be bad actors? Maybe just the "entry" and "exit" MN? Plus one in the middle?
2) Three-letter organizations don't necessarily have to pay for DRK (hacks, seizures etc)
MOST IMPORTANTLY
3) Even if there was only a 1% chance of your anon transaction getting de-anonymized by bad actors would you really take that chance? And if it were a 3% chance?
You take my point I'm sure.
#1. There's no way of knowing which MNs are the 1st and last points, you'd need all or them.
#2. Forget about defeating the NSA/CIA/MOSSAD/etc. You're not equipped. Not even remotely. You have no fucking clue at all what you are up against. 3 letter agencies aren't going to cock about buying MNs or devising supercomputers to crack encryption. They are going to bundle you into a van and cut your genitals off. Or kidnap your children and cut them up in front of you.
#3. You are 100x more likely to give yourself away via other channels than by having your DRK transactions traced.
Arguing about MN security when you could completely control the blockchain for a trivial cost thanks to centralised pools is obtuse.