I'm not sure that's quite true. High tech marketing and profits may be conflicting with environment considerations, but those are not technical issues.

I would argue that after many years of customisable/repairable desktop PCs and servers, it is clear that a more modular and standardised design is a good thing in most ways. It tends to be gamers who are the big upgrade-in-place fans and will look at things like new CPUs or graphics cards or even motherboards, but the modularity and standardisation are also good for simple things like adding more storage or RAM, or replacing a failed PSU or drive in an otherwise working system.

Even if you never use the flexibility yourself, an old PC can potentially have the storage devices wiped or replaced for security and then be passed on to another user. That might be a recycled home PC going to a less developed country where someone otherwise wouldn't be able to afford one. It might be a business clearing out some old pro-level equipment that finds its way to a homelab enthusiast. Either way, it's saving someone money and making more use of the equipment for longer.

Modern laptops and phones have fought against this modularity and flexibility, and that's not a good thing. There have been all kinds of arguments made about achieving smaller and lighter devices that people carry with them, or needing carefully engineered airflows to keep high performance components cool in limited space, or achieving better fluid resistance in case of accidents. Sometimes those arguments do have some merit. But let's not kid ourselves that all the sealed cases and ever-changing connectors (or lack of connectors) and active steps to prevent systems working with "unofficial" replacement parts aren't heavily in the interests of the manufacturers and doing real harm to both customers and the environment.