Choice seems to be an euphemism for everything related to private IT: For PCs there is Microsoft vs Apple. (I use Linux, but that's not for the broad masses currently.) For phones you either pay a premium to enter the Apple walled garden or you prostitute your digital life and get spied on by Google and its advertising cancer.
What would we say if there were only 2 car makers, 2 grocery chains, 2 companies building houses?
Look no further for evidence than New Zealand. There are two major grocery store chains (Foodstuffs, who own New World, Four Square, and Pak n Save) and Woolworths Group -- obviously we have the smaller Asian marts and produce stores too, but most people only have one of the big stores nearby to their towns.
There are two major building materials suppliers (Carters and Fletchers). There's one manufacturer of drywall (Gib) that is easier to get council plan approval for than any other cheaper manufacturers of drywall because they provide some material strength documents that saves the councils some engineering review time and effort.
We technically have 4 major banks, but 3 of them are just offshoots of big Australian banks and siphon the insane profits offshore.
The government keeps making investigation commissions into breaking these up, but doesn't do anything. The companies just point fingers back and forth at each other blaming "the competition" for price gouging. Meanwhile the recommendation from the politicians is we cut back on avocado toast, lattes, and our Netflix subscription.
Finland is nearly as bad. 20 years ago there were only 3 food chains. All domestic and playing the rules "no price competition". So food prices were about 30% higher than in Germany for example (these a very different countries so lack of competition is only one reason). Then Lidl (discounter of German origin) entered the market. The first years the incumbents fought it with unfair practices, but in the end it led to more price competition with everybody having to offer cheaper choices. 2 of the incumbents have since merged (with some regulatory limitations) so we are back to 3 players, 2 playing "according to the oligopoly book" and one doing things different, at least offering some choice.
Banks are not much better. There are a couple of small players additionally to the 3 big ones, but competition is limited to very few products. If you are interested in something else, choices are very poor.
If the choices are substantially different, you have a choice. Windows or Linux or Mac is a real choice - just because you'd prefer Haiku doesn't mean you don't have a choice. There's a huge range of android phones, and many of them have been reverse engineered enough to run non-google versions of Android (find out before buying). I have a PinePhone, but I don't use it regularly. It runs nearly-mainline Linux. Even things like Apache and X11 if I want it to.
I am typing this on a phone running SailfishOS. Still that's hardly a real choice for me who has worked 20 years as a phone or Linux developer. No banks, no public transit tickets, no city bike, no you name it.
Calls a texts work fine. I didn't try MMS, but on the forums people managed to make it work. Battery life is not very long, 4-5 hours of use or 20 hours of suspend.
I'm really happy to be able to run desktop apps (also on a big screen!) and have full control over my phone.
What would we say if there were only 2 car makers, 2 grocery chains, 2 companies building houses?