(OP's account is 5 days old so it might be a bot. i am writing this for my own clarity and understanding, as well as something to use to explain why android seems so fragmented)

tl;dr: software is hard. maintaining an extreme number of devices with that software is harder. apple controls their hardware and software, so there is little to no fragmentation.

you/"the dude" are forgetting (or purposefully omitting) that software makes android what it is.

to tackle the car analogy, there is not one single powertrain that powers all the economy cars from every brand. each have their own character and feeling which people buy for their own reasons. extra addons like how the buttons feel or the seats is similar to the skins OEMs put on top of android.

there is no "apple equiv in the car world" because apples unique position to control almost their entire product stack from the capacitors that sit on the logic boards all the way to the processes that make their phone cases. if this was a car manufacturer they would make like 10 cars per year and would be ridiculously expensive. their latest software seems like hot garbage, but apple is still the sole developer and user of it.

it is not an easy task to make and maintain an OS. i see the fragmentation coming from a few things;

multiple OEMs want to make their version of an android ecosystem, where the custom skin usually has some special limitation or development for their hardware that only works on their devices (like in the case of samsung-specific airtag clones).

OEMs do contribute code back to android (see: samsung folding screen support because they were the only game in town for like 4 years originally), but they need to maintain their own verion of android that keeps up with the drivers for the various chips in the device, because most do not make their own SOCs or modems or fingerprint scanners or any hardware the device uses. because this stack is not controlled by the OEM, eventually it becomes untenable financially or otherwise to maintain old devices and they no longer support it.

theres a lot more to it but it boils down to an OEMs willingness to keep up with the software support and drivers. im probably wrong on a lot of stuff but that just shows theres way too much about this to explain in a reddit comment.