Video games are not childish. The original PONG was put in a BAR. Actually, it was kind of a past time for people on a date to play Pong together, most likely 18 or older since it was a bar in 1973.
The whole "childish" thing started when they went to the home. Truth be told, originally Video Games were a family activity. When I was a kid, I would watch Saturday Morning cartoons and eat pancakes with my middle-aged mom and teenage sisters, then when Pee Wee came on, we'd fire up the Atari 2600, sometimes with as many as 4 player games of Super Breakout or 2 player games of Combat...or take turns on Pitfall...and play together. That all stopped with the NES.
And even then, when I had my first NES as a kid, mom played Tetris OBSESSIVELY - she was 45 around that time. To the point she had post-its of her level 12 high scores on the cart. My gradschool sister was playing things like Ultima and Dragon Warrior, and had a 386 with Monkey Island, Freddy Pharkas, and the adult-oriented Leisure Suit Larry on i it that I was not allowed to touch.
To me it's not just for kids. Of course, I think a lot of the judgemental b.s. around video games comes from people who are insecure that they are truly an adult or not. Adulthood is when you pay your bills on time, manage your committments to do the least damage possible, and get your "job" done - not whether or not you escape via some electronic device filled with fantasy.
On the comment of DOS/CP/M being scientist type stuff, definatly a product of the tech of the time. I work with people in science/STEM, and some of those guys can't even cd\ their way out of a paper bag let alone find the folder to click on half the time in File Explorer. Heck, my biological side of the family is all STEM and they were the jerks as a kid telling me that if I press one of the Function keys it will "kill/break" the computer. Now I make my living using things way more risky than the 12 Function keys on a 104 key computer keyboard. The tricky part about STEM types and computers is getting I.T. to get along with their bizzare and often highly specialized software these days, some of which is still using outdated technologies due to government regulations - like right now, I'm fighting with ActiveX controls in a "dead" browser in 2022 (rolls eyes)!