Being an f/4 lens user for APS-C, I can vouch for it's value, for me.Surprised at the number of f4 lenses appearing. And people singing their praises. My P7-14 gets so much stick for being a slow f4 In comments on various forums and reviews. Plus lacking the ability to take filters without the use of a diy hood, or the use of blu tack.
At my age, I cannot handle a 70-200/2.8 for 5-6 hours, to shoot sequential field games (football/soccer/lacrosse). That is too much weight for me. The f/4 lens is HALF the weight of the f/2.8 lens. Yeah, not as good as the f/2.8 for night games, but "good enough," for me.
I think that is the thing. For most people the f/4 lens is "good enough."
The extra cost, both dollar and weight, of the extra stop to f/2.8 is significant, and not worth it.
As for your P7-14.
For me, many of my wide shooting is outdoors, where f/4 is not an issue.
However, back in my film days, the core reason that I got a 24, rather than a 28 or 35, was when my back was litteraly up against the wall. So for interior/indoor shots, yeah f/4 could be an issue.
BUT, today we can shoot at ISO levels that are beyond what I could even dream of 40 years ago. My standard color slide film was Ektachrome or Kodachrome 64. ASA/ISO 64. My fastest color slide film was High Speed Ektachome ASA/ISO 160, PUSHED to ASA/ISO 320. I think that is something only us old-timers can relate to.
BTW, in my father's day, it was Kodachrome at ASA 25, and his fastest lens was a 50/2.8.