These prices have been plateaued for years, they didn't just reach these levels last year.
Plus, you said earlier that there were few WW1 enthusiasts, a big reason to stay away. The gains from both of these older sets tell me there were plenty that would plunk down big money for WWI sets.
Also, re: your comment that the market has changed, you're right. There are many more AFOLs and Lego collectors now than there were eleven years ago. The secondary market is MUCH larger.
You're welcome to do what you please with your money, but I think you are way overthinking this. People will pay $ for SC. They have in the past, they will again.