It's Apache. It's what it does best.

Computers aren't magic. Apache httpd isn't magic. The only reason it can run out of memory is misconfiguration.

Who said anything about magic? Apache's default config is crappy and it's a bloated web server. It will bring down any VPS to swap of death unless you lower MaxClient etc with even moderate amount of traffic.

More modern web servers (and more lightweight) don't have that problem. They work for most configuration out-of-the-box (and perform better).

I don't know how Apache is configured on this particular router, but I can spot ten httptd-processes in on the process listing. So yes, Apache is likely both a bad choice to start with and beyond that, it is also poorly configured.