A few reasons.
1. Apps with ads drain batteries.
2. Apps are scaring folk. Read from http://arstechnica.com/security/2015/11/new-type-of-auto-rooting-android-adware-is-nearly-impossible-to-remove/
It's a rough time for App companies. They should be screaming at Google to close the gap.
The decision to whether build a native app or a mobile website entirely depends on your end goals. If you want to develop an interactive game, then developing an app is probably the best option. But, if your goal is to reach out to a wider audience with mobile-friendly content, then building a website is the solution. In case, you decide to have both a mobile website as well as a mobile app, then it's quite rare that you might get the app without already having a mobile website in place.
Clavax is a mobile app company dedicated to the design and development of intuitive and interactive applications for mobile devices, enabling clients to reach out to wider audiences with their anytime, anywhere availability.