I'm not sure how those other browsers are in terms of memory requirements, but Dillo runs fine with low memory (assuming you load normally sized pages). Here is an example where Dillo opened the single page HTML5 spec, which is 12.9 MiB of HTML, and google.com (sizes in KiB):

  % ps vp $(pgrep dillo)
      PID TTY      STAT   TIME  MAJFL   TRS   DRS   RSS %MEM COMMAND
   919059 pts/1    S+     0:01      0   458 59425 46884  0.2 dillo https://html.spec.whatwg.org/
   919584 pts/6    S+     0:00      0   458 28589 17360  0.1 dillo https://google.com