good laptop brand for servicing

The common business model is to make laptops that meet the 'demands' outlined in the proposal of the machine, and one of those is not for the sort of servicing you seem uniquely used to. Commonly when laptop parts depreciate in performance you need to buy a new laptop, not simply "moving components between similar models". This is especially impacted with the common move to simulate the Cell/Smart Phone market, where consumers replace models 'every couple of years' and pushed the prices down to match (Walmart laptop off the shelf $249 i3 8GB DDR3 600GB HDD W8 DVD) making the component costs normally more 'expensive' then to simply replace a machine outright (same for Cell phones, try buying a new keyboard / screen / etc. for one is more expensive then buying a new phone).

Honestly no one is making DIY laptops anymore, they came and went. Some forums do exists of people whom 'hack' a specific maker's lines of products as you did, but they are unique people with the skills and insight to do those and doesn't mean that it continues (as you are mentioning) as time goes on. Even Alienware isn't as "modular" as they once were famed for, especially in the laptop designs.