why should i care that the content i create is accessible to all? The content on my website would have no relevance to somebody browsing in africa or asia. Furthermore, despite the fact that small-screen phones with web browsers exist, that doesn't mean that people actually use them to browse the web. I'm not going to waste time and energy targeting a browser that there's approximately 0.00001% of somebody actually viewing my site with. and it's not like the prevalence of 100px-wide screens is increasing.