You're not factoring in denominated units (and subsequent rounding at send) and "dead change" being sent to the network to remove linkages in future tx's.
It was a simplified example explaining transactions in general. Remember: the issue we're discussing is the average user deanonymising themselves through inadvertently. Dead change and denominated units do not solve the problem when the user has 50 DRK in their account, they send 20.72368 DRK to pay for some dodgy item, and then because they have some crisis they empty their wallet and deposit the entire remaining 29.27632 DRK on an exchange. Normal actions resulting in unavoidable and unwitting deanonymisation.
I know you are capable of it, we had a few posts with each other, so i know you are not someone who doesn't understand things.
The thing is you arguing on a wrong assumption about darksend!
Its realy not how it works if you use darksend.
Ill try to give an example.
If you have 50 drk in addr1
after starting the darksend denomination process you have (for example):
10 drk in addr2
10 drk in addr3
10 drk in addr4
10 drk in addr5
1 drk in addr6
1 drk in addr7
1 drk in addr8
1 drk in addr9
1 drk in addr10
1 drk in addr11
1 drk in addr12
1 drk in addr13
1 drk in addr14
0.1 drk in addr15
0.1 drk in addr16
0.1 drk in addr17
0.1 drk in addr18
0.1 drk in addr19
0.1 drk in addr20
0.1 drk in addr21
0.1 drk in addr22
0.1 drk in addr23
0.1 drk in addr24
so now all these addresses contain drk which has been mixed in the process of darksend with other users who also started the darksend mixture.
So there is no direct connection between these addresses.
so now you send
20.72368 that means darksend will use your previous mixed addresses - for this it will be something like:
addr2 + addr3 + addr15 + addr16 + addr17 + addr18 + addr19 + addr20 + addr21 - this will add to 20.8 - you have to pay 20.8, the difference goes to the miners exactly for the fact wo don't want any change address! (you could have also send 20.8 instead so you wont sponsor the miners)
so now these addresses are all gone out of your pool, if you now spend the rest, there is no connection between these addresses used in the first and the ones used in the second send right now.