People are making so much of this when it seems so much simpler. Qualcomm likes buying high-margin businesses, and Arduino is a high-margin business. Gross margin on their boards is over 90% (hence why you can buy a Chinese clone of a $30 board for $3) and this trend shows no signs of slowing down. The TI equivalent of the $30 Arduino Uno is $5, and it's a true gateway product.
You seem to equate gateway product = affordable but, IMHO, a gateway product is something that people who are not in the field are likely to stumble upon. I recently saw Arduino kits for kids at a small local bookstore, I can imagine someone thinking "hey this electronic thingy looks cool I'll buy one for my niece's birthday". On the flip side, people who don't know anything about microcontrollers are not going to look online for Chinese Arduino clones.
clone relies on hardware being designed and software written - this takes a lot of money, so you can't just count the final price of parts as the price.
Arduino is open sourced in hard and software which allows this cheap cloning to exist. It also helps a lot with software and docs, which makes it cheaper for them.
What's the TI equivalent?
It's probably simpler, Arduino knows the market has no future and wanted to get out and did a sales pitch to Qualcomm and Qualcomm accepted.
The Raspberry Pi Pico blows the Arduino out of the water in terms of computational speed, available RAM and so on, and it costs a fraction. I don't remember using an Arduino since the Pi Pico came out. And if the Pico isn't enough there are the bigger family members waiting in the wings. For me Arduino is mostly over. And then there is Espressif as well, they make some neat boards.