Model predicting flat-line even after moving average implementation

[anwar11235]

I am trying to run this notebook as is with latest IBM stock price data but the model ends up predicting the same flat-line

[cupdike]

Per the author, this is expected:

https://towardsdatascience.com/stock-predictions-with-state-of-the-art-transformer-and-time-embeddings-3a4485237de6#03a4

Reportedly, a linear model is the best that the approach can produce given the limited price/volume data of a single stock: