We can also note that POET now has a lot more cash. Small companies have to choose what to work on that will aid their survival on limited cash. This can slow down their ability to keep up with demand for their products. Development is notoriously slow within the normal cash constraints of business, and worse if cash is tight. 

I also guess that each modification of the OI and related tech gets easier for POET, as they have more experience with the processes and landmines of customization.