You personally can remain anon. For example nobody knows who satoshi really is but they can see a lot of his transactions but can't trace them to his real world identity. You can also use mixers to mask where your coins are going.
That is a very bad example. You can't use a person who hasn't used Bitcoin for years as a example. A person (if it is one) that did his best to hide his identity from the start. The average user does not fit this description. Someone who is actively using Bitcoin on a few services can not hide his identity. The services (i.e. ones that require ID) keep records of money transferred in and out, in addition to the addresses that you've used. A worse scenario would be if one of those services got hacked and all the information got leaked.
Because the ledger is transparent and permanent, one has to think ahead. If someone gets information in 2020, they can trace it all back to the begging easily (especially considering that there will be advanced tools by then).