Why do we not calibrate all devices to sRGB in the factory? The assumption is that every monitor is sRGB anyway. So why not calibrate them to that? That would make people see same color as intended on a wide range of devices.
Simple answer: because it costs. :) Some higher-end monitor models are indeed calibrated at the factory (and come with a calibration report sheet) but it would not be cost-effective to do so for all models in the product line.
Color reproduction varies even between batches of the exact same panel model, so it isn't possible to just use a set calibration for a given monitor model, it need to be done on a unit-by-unit basis. So to save costs, they instead determine the color reproduction curves of the "average" panel and use that for an ok but inconsistent result.
There are 2 major factor to this.
While it would certainly be possible to calibrate or profile each screen this would add cost to the process. Most users simply aren't that sensitive to this issue so it makes no economic sense to do so.
Its also worth noting that color reproduction is a function of several factors. Such as panel use age, operating temperature etc., but also ambient surroundings. So while this could be done it would be less than stellarly useful for the user in the long run, unless they operate in standardized lighting conditions and never use the monitor.
Certainly there is value in factory calibration. It simply means that the monitor can be calibrated to sRGB. And in some usecases the drift caused by age is acceptable.
The second problem is that is not technically desireable for the panel manufacturers. Forcing something like this on the manufacturers would be a bit like telling people that the the only graphics available graphics api from now on is opengl 2.0 no innovation allowed.
Business dictates that the manufacturers need to be able to innovate. Calibrating everything to sRGB would slow down development of panels that are significantly bettter in gamut than sRGB to evolve. Second not all display panels can reach sRGB. Developping ultra cheap panels also has a market function. No need to restrict innovation.
Calibrating to sRGB would ultimately not solve all color problems. Convoluted profile to profile conversions would still be needed. Display panels are precicion instruments and need to be handled like that if accuracy is drsired. If not then no big deal.