Correct me if I'm wrong, but the X series ThinkPads are the main competitor to the MacBook Pro series. IE, thin and targeted at professionals.
It's been years since an X-series has had a removable battery and the option for two of them. Decent-quality screens are a significant upcharge and even then barely match the Apple screen. And going over to their website, an X1 carbon 7th gen with a 10th gen Intel processor still uses LPDDR3, just like the Apple.
If you do a real comparison - beyond just "processor cores/speed, ram and disk quantity", you'll find that there really isn't a huge difference in price for specs and that you can comfortably buy the one you prefer and not feel ripped off.
I would say both the X and T series are MacBook Pro competitors. The T series aren't usually as compromisingly thin as the X Series but still aren't much thicker than an Ethernet port so they're still thin in my book. They're definitely way thinner than the P series machines.
P1 hits the sweet spot of thin AND pro. Same size as the X1 Extreme series, but geared toward business users. You can actually open it up and do some upgrades. RAM up to 64gb, up to a xeon processor, and the 1st gen is able to include nvidia quaddro gpus.
Ah yes, the P1 is an excellent machine and still manages to stay pretty thin. Its definitely an outlier of thinness in the P-series though, but is absolutely one which does not fit with my earlier comment of the P series being a bit thicker.
FWIW, most of the T series also have a good number of FRUs (field-replaceable units, what customers can easily swap out). Some models, especially the "s" versions, will have some soldered RAM but often the non-"s" versions will allow you to swap out both sticks. Wireless chips and SSDs are user-replaceable. Internal batteries are held in by screws and not glue so they're easy to replace when they age. Pretty easy to work on overall. My T460s is over 4 years old and still going strong.
I no longer care about removable batteries. I finally recycled my 2011 MacBook Air late last year, after 8 years of hard service doing development work on the go. The battery had half of what it once had, but the CPU and Ram could no longer keep up.
Removable batteries were more important back when batteries sucked, now they last the life of the machine.
This is just a matter of usage. MacBook Pro batteries have never lasted me more than ~3 years before signficant degredation (usually marked by swelling, needing replacement to avoid having the touchpad eject from the machine), and that number held from pre-unibody to post-retina. As an anecdote, the later generations seemed to degrade faster than the earlier ones.
Many laptops offer upgradeable RAM and some upgradeable CPUs. All laptops of my family have upgradeable RAM for instance. SSDs bays and M2 slots as well.
All LiIon batteries are around 80-85% of capacity in around 350-500 charge cycles given a decent controller and no excessive heat (which macbooks are overall bad at).
Upgradeable ram would be the only thing I’d want from Apple. With the advent of Dropbox & similar it’s been a long long time since I’ve run out of disk space. And as I’ve said before, I typically see laptops struggling to perform long before seeing their batteries give up on me.