As a senior data scientist and having held the position of manager of data science & ML, I can say the following. Often times, people are more caught up in doing the next 'cool' thing and elevating their own ego rather than solving the problem. That is, it's cooler to do it using a newer technique and they are actually after that accolade more than solving the problem. I've often had managers come to me and go, yeah you could use deep learning for this and my response is, "You do not need deep learning to do this." That would be overkill.
I'm not convinced the a+s=t trick is correct. The total number of letters t is not a constant. Changing the number of letters you send will increase the total t. The trick will only work if other people send less letters if you send more, thus keeping t constant. If you assume s
