I don't know where this misconception keeps coming from. FFXIV does not save combat logs to a file, and the combat log available in-game is not sufficient to calculate your DPS because DoT ticks are not represented in it. The parser that everyone uses has two options available for parsing:
- Memory reading: This one is less accurate because it has the same issue as the in-game log, being a lack of DoT ticks.
- Network Sniffing: This one reads the actual network packets the game sends and receives. It's not possible to detect it from within the game without installing a kernel mode driver, and it's more accurate since it can sniff the dot tick amounts from the packets. Only disadvantage is that it doesn't work when the windows firewall is enabled.
The .log file you are talking about is generated by this program, not by the game. If you don't believe me, delete the log, go hit a striking dummy without your parser running, and try to find the log that the game allegedly saves.
Well, they could close down many avenues of botting...
- They could disable input from a non-physical device... But that would completely break the game for people needing accessibility features, and dedicated botters could and would make kernel drivers to mimic a physical device. And even if they made that impossible, it would be cheap to make an actual physical device that's controlled by bot software.
- They could limit where and how the game can be run by for example having anti-vm detection and only allowing the game to run in true fullscreen... But that would be a dreadful play experience for legit players, and it could be worked around by kernel hooks. And many virus scanners automatically detect anti-vm measures as malicious behavior.
- They could disable trading, but then they would just use the marketboard to sell gil... And if that was made impossible too, it would severely impact real players...
The moral of the story is that every measure has a countermeasure, and while it would indeed affect bots... It would only do so until they have worked around the issue, while real players have to deal with it forever. Bots are perfectly content to put in the work to keep their cash flow going, and all their tactics exist because they work. They wouldn't be spamming the main cities and the novice network if that didn't get them sales.