Modular phones aren't exactly new concepts. They sound great in concept but these yet to be a proposed one I think really works in practise. The problem is that the ability to add remove components does a couple of things; add connectors that could get faulty, adds weight, adds bulk, adds materials. Also, unless the concept really takes off, there's almost no chance that the changeable parts achieve a big enough economy of scale to bring the prices low enough. There's also more and more features being packed into the main board and they often need to be integrated more tightly with the other components; for example upgrading the camera might necessitate also upgrading the CPU and RAM. Upgrading those might require a bigger battery. Cool concept on paper - but without some economies of scale I think it's unlikely to grow outside a niche. I hope I'm wrong.