This analysis by Benedict Evans is right:
Mobile is not a subset of the internet anymore, that you use only if you’re waiting for a coffee or don’t have a PC in front of you – it’s becoming the main way that people use the internet. It’s not mobile that’s limited to a certain set of locations and use cases – it’s the PC, that can only do the web (and yes, legacy desktop apps, if you care, and consumers don’t) and only be used sitting down. It’s time to invert that mental model – there is not the ‘mobile internet’ and the internet. Rather, if anything, it’s the internet and the ‘desktop internet’
So, mobile today does not mean ‘when you’re mobile’. It means ubiquity – universal access to the internet for anyone at any time. People use their smartphones all the time, very often when there’s a PC in the same building as them or the same room, or on the sofa next to them.