imo it's all about good alternatives for enough use cases. when floppy disks were going away it was being quickly replaced with things like CD, and while the latter had it's growing pains if i recall, it basically still covered most use cases (at least as far as I remember, though feel free to correct me on this).

SDCards: it's similar here, the first few generations that did this did it too early even in places like UK, Canada and USA while the internet was mostly ubiquitous enough to replace sdcard for quick sharing of files it wasn't until sometime later that we really started getting 64GB and 128GB storage on phones. Nowadays ofc, 128GB and more is super common so there's less need for expandable storage. However, SDCard isn't just about expandable storage, it's also about data transfer. It's ok if you're like me, I live in a city with 5g data and >1Gbps wifi and internet everywhere, jsut upload everything to google drive or whatever. But this is much more of an issue when i was in india for example and needed to switch phones. Transferring all those photos, videos, pdfs etc via a usb cable was really slow and annoying, back in the sdcard days i'd just pop out the card and pop it in into my new phone. This is crucial - in general we need to keep in mind as many use cases as is reasonable (forget india, there are plenty of places in USA that have bad data connections and poor internet what do you do if you live somewhere with poor wifi and data and need to switch phones?). That being said, it wasn't bad, especially these days, fast internet and "everywhere fast data" is becoming more and more common and the sizes of the built in storage is large enough.

(Note: I could go on about Apple/Google etc shift to force people into using cloud services more and how INCREDIBLY US-centric that is).

Headphone jack: As i said, the important thing is to keep in mind different use cases. Yea bluetooth is great and things like square payment has quickly replaced their headphone jack based connection with bluetooth but there are too many uses cases here from people who rent cars to people for whom bluetooth simply isn't reliable enough yet. Bluetooth is not a simple drop in replacement like CD was or even built in storage to a large extent - bluetooth devices need to be able to power themselves for example.

Honestly to me, removing the headphone jack so you can sell more bluetooth headphones (which is usually cited as a possible reason?) seems silly - but that's just me maybe. Bluetooth is ubiquitous and convenient enough that those who are up for it will already be using it, or looking to use it. But you're not going to convert too many people into using bluetooth just by removing the headphone jack - worst case you're gonna get a lot of people buying those little dongles. Do those little dongles really make that much money? Is it just about shaving whatever you can, i can't imagine a headphone jack adds to much to the BOM but maybe every little bit counts?

Ultimately with any of these things it's all about thinking about other people in other situations. Yea for me, i don't really take a lot of photos to begin with and was lucky that for the most part i lived in places with good data and internet so the switch away from sdcard was a no brainer. I've been using standalone music players since before ipods were a thing so, again, no headphone jack doesn't bother me. I didn't really rent cars or use any of the many myriad of devices that used the headphone jack to connect either so again, meh. The problem is, there are entirely too many people for whom these things are crucial. And as much as I hate to say it, this is a bit of a "check your privilege" moment as well (I am about as big a google fanboy as you can get, but YIKES, that company - i'm positive, has NO IDEA that other countries exist).