Good luck finding a laptop from another brand that is more upgradable than your MBP.
Most laptops had socketed CPU's up until 2015 when Intel dropped socketed mobile CPU support altogether with Skylake. I originally had an i5-2450M in my Dell XPS 15 and replaced it with the second fastest mobile CPU in the Sandy Bridge line-up (i7-2860QM). It made quite a difference in Premiere render times. Very handy indeed. Even back in 2012 there were laptops that were relatively thin that still had dedicated GPUs, this is true even more so today with many Ultrabooks including nVidia 1050ti and 1060 graphics. Some even now have 2080 MaxQ designs where they are practically as thin as a 2013 rMBP and have near-desktop level graphics. Apple continually sacrifice good thermals and upgradability for a slimmer form factor (look at the 2018 i9 MacBook Pros or 2013 Mac Pro. This has been key to their design ethos (even leading to the inherently flawed butterfly keyboard that fails when dust gets under the membrane, they've just announced that their 2018 MBP is covered under their keyboard repair program). In saying that I do really like my 2013 rMBP. But when it dies I'm going to get a 15" ASUS Zephyrus 2080 RTX laptop and dual-boot Windows 10 and MacOS, I won't have to worry about keyboard issues. (I'm currently dual-booting on my 2017 7700k custom rig).
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Well as it was near the top of the threads due to other people posting today not far...
Still haven't answered the question yet though, somehow doubt you will.
I'm not familiar enough with other models outside Apple but here are a few I've worked on that had socked, upgradeable CPUs (within their respective micro-architecture generation, ie an i5 2540m can be upgrade to a 2860qm)
Dell Studio 2009 series>XPS 2010-2011 series
HP DV6/DV7 2009-2012 series >HP ProBook 2010-2011 series>HP EliteBook 2012
Most MSI/Asus laptops circa-Skylake.
I'm sure there are other laptops and brands that I have left out but again, I can't comment on what I'm not familiar with.