With all due respect, you sound like Homer bemoaning the advent of writing and it's effect on memory.
> Composing text deliberately by hand forces a more measured pace of thought and development of ideas
Penmanship is orthogonal to the ability to write by hand. I for example have atrocious hand writing and can still easily write my thoughts down, and often do. Other's will have trouble with my written notes, but they're not meant for external consumption, I type for that purpose. Cursive versus print style writing are mostly interchangeable for writing down ideas, and learning to write well in cursive takes up to a few years. It may not be time well spent.
> I've even heard educators say that it's not worth teaching arithmetic anymore because everyone has a computer, or a phone with a calculator.
I know a number of teachers, and try to follow trends in US education, and I've never encountered this idea. Are you sure you aren't constructing a straw man here?
> Spelling is also not given much importance these days, with "creative" spelling being acceptable at least through the elementary grades. Even in high school it isn't given a lot of weight.
At least in the US, this is not the case. Any state that uses the Common Core follows these [1] standards, including phonics, building words from stems, and differentiation of homophones.
>If you don't learn the meaning of words
Who's saying anything about this? This tech looks like it just guesses at the banal pleasantries you type at friends and colleagues 1000s of times per year. I know I write the same phrases almost to exhaustion, I'd love to autocomplete the trivial stuff, and spare my hands an wrists. *note there's a great accessibility story here, where people with manual impairments will be able to answer emails more easily.
> Students are losing the ability to think.
Are they really? I'm not sure there's any evidence of this actually happening.
> More and more we are having our worldview formed not by critical thinking and development of our own opinions, but by what Google and other big media companies tell us.
How is this any different than mass media dissemination of information from the previous generation, when everyone watched the same 4 TV channels and read the same 1 or 2 newspapers.
[1]https://www.spelling-words-well.com/common-core-standards.ht...