When Android first launched, thanks to its open source nature, there were plenty of custom roms users could choose from. This did involve voiding the warranty but in order to get better performance, features and even remote bloatware, many users opted to give these roms a try. From this companies like Cyanogenmod rose, thanks to their popular alternative. However, it looks like due to upcoming changes, custom rom development will drop and to a certain extent disappear. Here is why:
Security
With more and more personal data carried around on phones, security has become even more important. In the near future most Android manufacturers are expected to follow Apple and create security specific hardware for their phones. This will mean that loading a custom rom will remove all those security features.
Payments
Tied to the security of the phone as mentioned above, Android pay and other pay services will require some form of on phone hardware security. When buying a new phone customers will look for the Pay features and are unlikely to buy phones that do not support it. Already some phones disable the pay features if they detect a different rom.
Features
Most features that led people to custom roms have moved over to Android proper. Everything from skinning, night mode etc are now features of different manufacturers. Even split screen is coming officially. Even some features like iris scanners etc will also require hardware and security tie in, killing any chance of those being available on custom roms.