Scalable UX/UI patterns - the real cost of your HTML select element

When developers are talking about scale issues, they usually mention auto-scaling groups, load balancing or shedding, bundle size, code splitting, chunks caching, availability zones, and so on: not everyday pieces of a codin' cake. The truth is that, however, scale issues are not so distant as they may seem. This talk tackles user experience and design patterns at scale, from the perspective of simple elements, like a picker (HTML select), in large applications. How does such a trivial element affect overall scalability?