At the risk of being very wrong about this, but whilst i have seen that end-users have seen a decrase in text they need to read to get things done - i haven't seen much of the same trend for developers, engineers and sysadmins over the last 5 years. (Sure you can argue that a lot of new server-side software is more simple to configure, but as a tradeoff we now have a lot newer technology such as virtualization,... around that.)
Looking at my Todo List, there is an open task of - create a few "self-help" videos - that has been open for a year. Its a lot of hassle but probably the route that i will be going down next.
Look it's not black and white, I could be wrong about this entirely I admit that openly. With regards to your comment on self-help - Two things that make it work for me - I don't have to Remote Access a client's pc and spend my time setting up somebody's Imap on their computer. From Google's standpoint, you are providing a website with a nice big variety of related content in relation to the main services you offer.
Heck, il admit about 50% (if not more) of people I send self-help links to don't do it and we still end up doing it for them, some I even have to go to and do it on their devices. --- but that's building a solid support relationship. The other 50% are saving me time and thinking, these guys have it together.
For those who do use your self-help they will return to find another solution and so returning visitors are also great in the eyes of Google and it's great for your brand.
Perhaps a thing a should mention and why we have a difference in opinion is that I am from South Africa more specifically the Eastern Cape. Here we are quite young as compared to the rest of the world in the online space.
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Developers, engineers, and sysadmins are not your average person they are attuned to finer details because if you leave a cap of a function or just omit a semicolon your site crashes, or things go wonky. It could also be that people who are more detail orientated naturally make for better developers...
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If you look at recent statistics on the growth of voice search you will see it growing between 9 - 10 % per year from what I could find.
Here is quite a nice article on it:
https://www.oberlo.co.za/blog/voice-search-statistics . Note where it says 71% of people prefer voice over typing. That was in 2018
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To end this off from my side I don't disagree with you, though my grammar may be horrible I try to work on it still because there are high-end clients that would drop me in a second because of it. It happens still.
I myself don't use voice search, as pointed out it's still very rough around the edges in terms of giving superior search results. Google still struggles with natural language not just in voice searches but on text-based searches too.