Originally Posted by xeno000
Yes, but. It has been almost 70 years since WWII ended. In that amount of time Zola could have gone from SSR custody to any one of a number of countries or US government agencies. With Zola's advanced scientific knowledge, he could easily have bargained for his freedom by cooperating with the US military, a la von Braun. The SSR had the Tesseract, after all, and Zola was the one man on Earth who had any idea how to use its energy. He would have been an extremely valuable asset and there is no reason why he wouldn't have been recruited by the MCU version of Operation Paperclip.
Had Zola made such a deal, securing his freedom in exchange for aiding the US, he could easily have continued working on the Winter Soldier project in secret. Perhaps Zola had his own allies (HYDRA remnants, Zemo) who retrieved Barnes from where he fell and froze him until the scientist could proceed with his experiments. After Zola retired and when his body was failing due to age, he would have had a lot of incentive to work on his android body prototype and Barnes' artificial arm. There is a lot of leeway to make the Zola/Winter Soldier story work, if that's where they're going.
I like your thinking....I'm just saying that Zola couldn't have been the one to "rescue" Barnes from his fall. Somebody else did that, and maybe Zola started going all Winter Soldier on him some years later. Maybe, as you say, some element of HYDRA found him (I still think they're the most likely ones) and recognized him from Zola's earlier experiments (as shown in CATFA), and kept him in the hopes/knowledge that the professor would return to them one day.