We do not have Rashbam’s commentary to Genesis 2-17. It appears to have gotten lost along the way. Unlike other, apparently more popular commentators, who had numerous manuscripts copied, only one manuscript of Rashbam’s reached the modern world, and it was lost during the Holocaust. The only reason we still have access to much of Rashbam’s Torah commentary at all is because of an 1880 printed edition of that manuscript.
Why was Rashbam so neglected?
It seems his take on Torah, for all its brilliance, was not as appreciated by the Jews of his time and for many centuries to come, because when he determined that the peshat, the plain-sense meaning of the text, differed from halakhah, Jewish law, Rashbam chose the plain-sense meaning. This approach wouldn’t be duplicated until the modern era of scholarship. What we learn is that Judaism as practiced does not always line up precisely with the Torah on a surface level. There are customs, ethical concerns, other influences, and ongoing creativity that generate the Judaism of each age. Rashbam himself hewed closely to rabbinic Judaism derived from the Talmud, and it seems his Torah commentary was almost academic, meaning learning and scholarly clarity for its own sake, not for practical instruction.
For us today, Rashbam’s Torah commentary remains a guiding light in the spiritual practice of Torah study, if not in halakhic guidance.