Warehouse was the best theme for PS1.6 and is so flexible you can configure it in many different layouts. If you're creative there are few limits. Yes, it aged and it could be made more mobile friendly for sure but it's still rocking sales for me. Not to mention the few big modules that came with it - the most powerful mega menu, homepage editor, etc..... The developer is not paying me money to advertise, it simply gets the job done.
Regarding mobile crawling - you know very well that google does not index and show 100% of every shop. The graph you gave above definitely had some other issue for not showing in the index.
Unfortunately the dev is reluctant to keep the work on 1.6 version and it's currently even dropped from the package if you buy it from themeforest so I don't know if when contacted he will send the 3.8.7 version that is the last for TB and PS1.6.