I bought my first and only Macbook Pro in 2006. Over time, I upgraded the RAM to max it out and I upgraded the disk drive several times as storage prices fell. Due to all of this upgradability, I was able to use this as my primary device for fourteen years until the GPU finally crapped out. While I'd never had any issues with the laptop before the GPU died, it was made up of commodity components that could easily be sourced and replaced by skilled technicians at third-party shops. Due to that, I never felt the need to get AppleCare. It will likely go down as the best laptop I've ever owned.
Contrast that with the current Macbooks which can't upgrade the RAM or storage after purchase. This means that if you want to build a laptop that lasts a long time, you need to pay Apple their extortionate fees upfront for RAM and storage as there is no ability to change your mind later. Most of the components can no longer be sourced by third-parties, so you'd better max out AppleCare as well. And after that expires, if any component dies on the motherboard, even a $5 IC or capacitor, your only option is to pay Apple $800-$1500 for a refurbished board since they refuse to replace individual components on the board. And if you maxed out the RAM and storage to future-proof your machine, you'll be paying the upper end of that price range. Also, depending on the component that dies, you may lose all of your data in the process. And that's only if Apple doesn't refuse to service the laptop in the first place. Tally that up, and it's hundreds, maybe well over a thousand, dollars just for future-proofed RAM and storage, hundreds for AppleCare since third-party board repair is virtually impossible, and well over a thousand after that if any component on the board shits the bed after AppleCare expires. Macbooks have essentially become premium disposable laptops.
So while the option to customize your Macbook via build-to-order will certainly alleviate some of the TCO issues that modern Macbooks present, they're still a very far cry from what they were in the mid 2000s and early 2010s. It's a shame because the M-series chips seem pretty great, but I personally can't justify the enormous hike in TCO. But based on their sales numbers, I don't think my priorities mirror the average person and I highly doubt Apple is missing my business.