Everytime someone says that I look around at the cracks in the sidewalk, the mold in the walls of my house, the empty lots and single family homes in one neighborhood and the OD'ing junkies in the next neighborhood, and I think, if there's less work that needs to be done, then why isn't anyone doing all this work that DOES need doing?
What you are describing is not a problem of lack of manpower, or productivity. It is socio-political. If it was in the interest of the status quo to actually fix all of these issues in the developing and developed world, then rest assured you'd get a machine that could clean and repair infrastructure in no-time.
It is already bad that people are getting 4 year degrees and ending up in an useless job. The vicious, even worse part is that it still manages to extract $100k+ out of them in the process.
Advertising share of gdp is at ~2%. Healthcare share is ~20% and rising. And from my experience as a non- It worker, most of the jobs deal with useful stuff (however inefficiently they do so).
Ask anyone who works in healthcare: the portion of their work that is growing is mostly "bullshit". Insurance companies and other payers like Medicaid are constantly innovating in new techniques for delaying and denying payment. It isn't clear how much of that is just a feedback loop, as providers hire more admin staff to deal with billing and then feel pressure to increase billing to pay for that staff, in response to which payers feel more pressure to deny payment, but there's definitely a lot of "bullshit" going on.
Also, it's not so much about GDP per industry, but perhaps if you have the GDP per capita at different industries, we could take a look at what kind of jobs are being created and that actually needed.
That is the issue. With increased automation, we don't need people to become more productive. We just need people to continue being consumers of all of the crap that we keep producing for super cheap. And this is the case in most developed countries.
Think of the amount of bullshit jobs that we keep around just for the sake of justifying one's worth as a productive member of society. Think of all of the "me-too" apps that we see for every closed platform. Think of all of the overpriced espresso you pay at the hipster cafe to some barista that might be $100k in debt for their French Literature B.A, and dreams of becoming a journalist writing for $150 a piece to HuffPo.
None of these people are actually needed by the system, except for their capacity to consume. UBI can be a solution for it. If it actually becomes universal and it is used to replace the broken means-tested welfare methods, I'm all for it.