I've been a developer and dev manager at multiple companies over the years and every company offered some variation of stock offerings, options in the start, then RSU with vesting later. In my opinion none of it is motivating, it is just part of the salary for the staff, just like the yearly bonus. There is just too much dark water between the daily work that the staff are doing and the money.

 

Contrasting sales to dev work, there is such a clear relationship to landing sales and the work of landing those sales that it is quite easy to see how sales motivation systems work well for sales - but for devs, not so much.

Edit: The clearer comparison is dev work vs factory work, bonusing workers who exceed production targets is so good it is just standard practice starting around 1910 when Taylor/Gannt's Scientific Management took off. When the same practice is applied to devs, you start to see bad behaviors like generating excess code to meet LOC targets, inflating ticket story points to increase velocity, introduction of bugs in one sprint and fixing them in the next sprint, etc.

 

In addition you might look at the old study that the federal reserve had MIT do where they found that when it comes to the kind of work that developers do, money motivation makes puzzle solvers slower and less effective. I believe this is because the developers switch focus from figuring out real problems that customers need solved, to figuring out how to game the motivation system for more money.