BMW's "i' brand was an experiment to understand newer technologies and the company knew it was not going to make huge revenue out of it. However, the "i" models have been instrumental in the future technology that the German company would adopt.
The brand "i" was used more as a testbed for new technologies, one of the most important being the carbon fiber reinforced plastic (CFRP) moulding. This allowed the company to produce a fabric which is almost the had the same properties as a carbon fiber, but this was a lot cost effective - this enabled BMW to use it in other models.
So how does the "i" brand is under threat? Well, BMW in a recent statement said that it will be focusing on its electrification programme on the 3 Series sedan, the X4 SUV, and unspecified MINI model. This leaves the "i" under a threat; however, BMW has not confirmed that the "i" brand will not be part of their agenda.
With Mercedes-Benz ruling the premium brand segment compared to BMW this year, BMW has to focus on electric technology on its existing models with better scope compared to the "i" brand. The German company can leave the "i" brand more for its experiment and gain new technologies.