None of these are Internet Explorer, the problem in question. Chrome and its Play Store dependencies are backwards compatible to much older phones. Android browsers even years ago had better web platform support than IE11.
I fully sympathize and believe that web sites should be as compatible as possible. It's the web apps that fall apart once you take away modern functionality.
> In the past, using a crappy browser was a matter of choice. Nowadays, the only people who use them are those who have no other choice.
This really depends on how much their actual lives depend on being able to use the web. If they live in poverty and/or third world countries, are their daily lives impacted by the web? What part of their life depends on what site exactly? Sure, communication is relevant, but we're already saying they have smart phones and thus data connections, email, and whatever native chat apps.
I'm not saying we should leave them behind technologically or that they don't matter or shouldn't have access to more information or knowledge, I'm just simply being practical with what is likely the real impact to their life.
In the end, I think web developers need to stop using ridiculous frontend tech for what ultimately constitutes static text content. The web already excels at that. Servers cache. Browsers cache. We don't need Vue to render a blog or article. Please leave such tech for SPAs and "apps" rather than sites or pages.