I spend a lot of time at another forum,
advrider.com which also runs the same Xenforo as the forum software and you can still customize the "style" for your liking. I'm no software guy, but if they can do it, why can't PM forum do it?
There is no "technical" barrier, no. Whether DB driven, templated, or static, coded in perl, php, ruby-on-rails, python, compiled-C or Glasgow Haskell, a website - or the toolset for building a site - had to start from a blank page at SOME point.
IOW ALL options existed. And generally do not vanish.
Even a purely static page can be rendered per end-luser choices .. or have all or portions converted/substituted. See 'privoxy', for one example if custom .css are not comprehensive enough for your wishes.
Site owner/manager "decisions" are a separate animal.
(S)he who feels enough NEED of extensive change to "cosmetic appearance" quite reasonably has to lift the load of making the changes at THEIR end.. at the rendering and display point.
I actually DID that.... for the old site.. Uber-complex .css to suit my need for far faster and easier reading and navigation.
I can no longer be bothered to do it for this one. All I have done is use a browser told to NOT load ANY graphics files.
BFD. To view a member's posted graphic, all I need to do is "open in new tab" and THEN it loads.
Good enough to lighten bandwidth load and regain some of the lost speed.
Got what I came for long since. Diminishing returns as screen-time now eats too much out of project time.
Such is life. Ever-changing environment. Ever-changing priorities, yah?