When I started my current HoloLens project, I've set the quality settings to "Fastest". This unfortunately didn't let me render pixel lights until I found out about the "Pixel Light Count" property in the quality settings. Adjusting it worked as expected. Because of another problem (https://forum.unity.com/threads/hololens-spotlight-horizontal-clipping-issue.507593/) I've moved to work on other issues first. Coming back to it now surprised me with the Pixel Light Count having no effect anymore. I can place a lot of spot lights in the scene and all of them are rendered on my simple quad object. My pixel light count is set to zero and I am using Forward Rendering. My Unity version is 2017.1.2p1.