Good architecture should not dictate how you live, but should instead be created to respond to the way that you want to inhabit it. It doesn't matter whether it is a new house, or the extension and alteration to an existing one. There is no 'one size that fits all'. We all have different priorities, tastes and needs to be met by the architecture of our homes. As Architects, it is our job to understand these, sometimes, perhaps, better than you do yourself. It is partly about the feelings engendered in ourselves as we arrive, and as others do too ('kerb appeal').
The Architect's fees for design may only be a small part of the costs for your project, quite apart from the actual building work. Depending on the site, scale and type of project there could be other significant costs, some of which may have to be met up front. You may need to undertake additional surveys and preparatory work. Some may be avoided by careful design. Clearly a site subject to requirements for extensive surveys, mitigation measures, developer contributions etc. will have a lower intrinsic value than one that does not.