"It all depends what 5G turns out to be."
...you're trying to debate this without having researched the proposals that are on the table? Let's be clear: 5G is about delivering up to 10Gbit per cell to far more devices than 4G could dream, largely by using a much higher number of smaller cells scattered all over hell and back. That's why they want higher frequencies; so that you don't end up with cells overlapping in urban areas. Read this, then we'll have a talk.
"It's possible that currently being in Bangalore where 3G services are both ultra-cheap and extremely patchy due to network overloading at peak times has coloured my viewpoint on this, but I do think that enterprise high bandwidth use cases such as VDI just won't see wireless as reliable enough for the foreseeable future and so won't be an investment driver for the technology."
What can I say except "you're painfully, overwhelmingly wrong". 3G services run on long penetration waves. They are slower than sin, and the technologies themselves are utter shit for dealing with an overload of devices. That's like comparing a mid-urban 17th century cobblestone road to a fully modern 18 lane freeway. Even if the traffic volumes are radically different, the freeway is dramatically differently designed - off ramps, no vendors in the streets, banning donkeys and carts, etc - that it just moves traffic more efficiently.
5G is supposed to be the equivalent of taking a modern 4G network and cutting the cell sizes down to 1/10th, while boosting the theoretical maximum cell capacity by 10x. All with a layer of additional technologies to help prevent interference, signal degradation and ensure better handoff.
So yeah, you're just wrong. "high bandwidth" "enterprise" workloads like VDI - which by the way, is rather low bandwidth and increasingly used by consumers, at least here in North America - actually work pretty well over 4G. They'll work far better over 5G.
I'm sorry you live in a technological armpit. I really am. But much of the rest of the world simply doesn't suffer those issues. Canada, for example, has LTE that works like a sonofabitch, and 5G will be absolutely transformative for us.
So yes, people are going to use mobiles for more than checking mail and browsing webpages, slowly. Maybe, one day, they'll install mobile that's not shite where you are too.
But "mobile that's not shit" technology already does exist. You need carriers that aren't shite. (Ones that split the cells and size appropriately) and you need a frequency layout that allows for "not shite" (high frequencies in urban areas to allow for smaller cells, etc.)
Some of us have these. We thusly don't have the sorts fo problems you describe, even on modern technology. The issue isn't the tech. It's the implementation. Which means that when 5G comes around, and splits the cells even more, whilst offering far higher bandwidth per cell....
...well, that'll change the world for a lot of us.