Personally, I found that with a proper accounting program such as (the free!) GnuCash, I've been able to handle FIFO and capital gains with a minimum of fuss. It just requires you to get started properly, and not be afraid of double-entry accounting.

Actually, I managed to retroactively figure my basies more than once simply by a combination of GnuCash and coinmarketcap.com. It took an hour or two, but the good news is that with the blockchain, all this information is publically available.

That said, keeping track of income from steemit in its three virtual currencies is the most obnoxious part of being a steemit author.

As an aside, it's theoretically possible with bitcoin specifically to identify every coin going in and out of an account, so specific identification isn't theoretically impossible. In practice... well, writing a program to do it for you wouldn't be that hard, I don't tihnk.