My old professor told me we will never dig up the real story of the Indus script, and I think she is wrong
I got coffee with my old professor in Chicago last week, and she mentioned that after 100 years and over 4,000 inscribed objects, no one has cracked the Indus Valley script. She thinks we never will because the texts are too short and there is no bilingual key. I pushed back hard on that. We cracked Linear B with way less material, and new computer work on patterns is moving fast. Give it ten years and a few more digs in Gujarat.
Guessing I'm the last guy who should weigh in here since I still get lost on a map of the ancient world, but your professor sounds like she has been burned one too many times. My gut says you are right though, and history backs you up, because nobody thought Linear B would fall either until some guy stuck with it and cracked it. Those Indus texts being short is a real problem, no question, but short does not mean hopeless when you have thousands of examples to compare side by side. Computers are stupid fast now and they will spot patterns in those signs that a room full of grad students would miss in a lifetime. Give it ten years, a couple of good digs, and somebody stubborn enough to connect the dots, and I would bet on the script losing.