*previous quote sniped*
It is identified in many cases because many user gave identity to exchanges where you can identify them if they use their service.
Just tell me if I buy new laptop/Mobile/Hardware wallet use public wifi service download new wallet and send BTC to that wallet how you will track me. It's not Bitcoin who lost anonymous nature it's user who did not care or don't want to be anonymous.
Ok here are few questions then,
1.Where is this previous address(one or many?) you are sending resides?
2.What was the previous address used for?
3.What transaction was made from the previous address?
4.How you got the coins into the previous address in the first place?
5.What are the transaction that you are doing with your new address?
6.Is there any repetition transaction that matches with your old address?
7.Does the area of operation of new and old address matches? (IP wise?)
8.Was there any conversion done with the previous address?(btc to real world cash?) If so where and to whom?
I could go on and but I hope this gives you an idea. Anonymity of bitcoin was not lost it never had any to begin with. Buying new laptop/mobile/hardware wallet doesn't add anything to anonymity unless your old ones are bugged, and if thats the case law enforcement has already have very clear idea, this new gadgets wont make any difference.
Regards,
BLife