Why are people , many people , some of whom say they have advanced degrees ( for example PHDs ) adding spaces everywhere ? Is it a thing now ?

[MrsTerryPratchett]

Just why ?

The books I’m thinking of are from the 1920s or 1930s.

See for example this 1994 facsimile of the original The School at the Chalet published in 1925. There’s definitely a gap left before the (many) exclamation marks. Maybe not a full space, but definitely more of a gap than is currently the standard.

Because I'm old and was taught 2 spaces after full stop and 1 after a comma.
So not a new thing at all

The link below gives some interesting information on the topic. Part of the summary says
“Printed work from as early as Shakespeare until the middle of the twentieth century was typeset in Britain with a space preceding the marks ? ! ; : and with two spaces following a full stop / period. A space followed the opening quotation mark and preceded the closing quotation mark…”
https://english.stackexchange.com/questions/590078/when-did-punctuation-marks-lose-their-associated-spaces

Typesetting and punctuation standards have changed and that’s at least part of the issue @MrsTerryPratchett.
I’m older so I remember reading books with gaps before the question marks etc. It’s not so odd that there hasn’t been a complete changeover yet.

If I type an unwanted space in informal contexts like MN or social media I usually just leave it, because it just doesn't matter and most people understand it to be a harmless little typo.

People with advanced degrees, as the thread title has it, are used to writing correctly in formal contexts and are therefore less anxious about demonstrating their capacity to write correctly when they are essentially just chatting with friends.