My personal pet theory is that bargain Android phones like the Moto G are now actually usable, as are cheap Android tablets - which wasn't necessarily the case a couple of years ago.
So, imagine with me, if you will...Bob.
Bob, two years ago, works in an office. His works computer is his primary web browsing machine (because he's a shifty skiver, natch). His home computer was his secondary device. His budget Android handset, used to replace a Nokia 6320 or similar, was his third device, really a last resort if the home computer was too far away, wasn't turned on, etc. because the home computer was much better for surfing the web than his (lets say) HTC Wildfire S.
Now, today. Bob still works in an office - we'll assume he's still a tricksy character who likes to check the web between assignments. His works computer is his primary web access machine, by nature of it just being there, as before. But now, he has a Moto G or similar current budget handset (or a Tesco Hudl or similar) that's actually worth a light, as most basic android devices have become thanks to efficiencies of scale at the high end filtering down - a Moto G is as quick as the Nexus 4, the previous years flagship Google handset, which is still not a slow phone, and has a similarly good screen and digitiser (unlike the HTC Wildfire S - can you tell I've owned one?).
When he gets home, he uses that phone/cheap tablet to quickly google stuff, get quick updates on gossip sites etc, rather than fire up the home machine - which he only uses for actual research (aka getting stuck in TV Tropes for four hours at a time, trolling wikipedia, whatever it is the kids do these days that requires lots and lots of tabs).
So the budget android handset has gone from being a tertiary device that was a bit of a PITA, frankly, to being a secondary device, getting much more use because they have suddently got so much better.
Correlation != causation but you've got to admit, the last couple of years, the quality and performance of <£200 android devices has seriously improved. My father, for example, barely boots his PC up unless he has to type an invoice, etc...everything else he does through a £180 tablet bought last year. It's just bob on for it, and loads pages faster than his Win 7 machine, is always 'on' within a second of picking it up, etc.