Your analysis is spot-on and the article very well written. I absolutely agree with all of your points. Unfortunately, I don't see an easy solution either. Users could be forced to solve captchas before playing but that could severely decrease the fun of playing if it's not done in an entertaining way...
The developers will need to be creative to tackle this but I wonder whether the team even recognizes bots as a problem. If that's not the case, there won't be any efforts to decrease their impact.
RE: Splinterlands - the bot problem in higher leagues.