Betty, it's really time for you to consider revising your rule regarding maximum post length.
For speed, efficiency, security, & our own encryption, we use database driven sessions, not file based sessions like you would do for images or video. Images & video cannot be database driven, only text, code, & scripts.
Large databases are easily stored & run on the servers. But if a database crashes, gets corrupted, lost, or hacked, a backup copy of the database is uploaded to the server from another server or from a hard drive in my home. These are uploaded to a database in lumps of pieces at a time, called packets. They can only be a limited size set by the servers.
Oversized packets, like that of a long story part, stop the upload, fail, & abort, or it tries to cut up the story part into smaller packets, so it goes through. That usually doesn't go well, & results is a corrupted part with bits missing, strange symbols turning up in the stories, or gibberish in the story part.
I can sit down & take hours to manually rewrite the data base for each oversized story part into comfortably small packets that will work & not corrupt. But I really don't have the time or ambition to do that with every oversized part that appears here. Perhaps paid teams of a dozen or so staff familiar with coding & data bases can do that daily coding at mega-sites like FMania, & DeviantArt. But I'm working & running this all alone, so won't be scheduling those many extra hours of tasks to do every day or several times a week.
Comparing us to them is quite ridiculous anyway. There is no comparison. You're comparing a multi-million dollar well staffed mega-web company, to a simple SMF forum run by 1 person with their pocket money. It's like comparing a visit to your friend's house to a visit to Disneyland & seriously wondering why your friend don't have a roller coaster & theme park for you. You come here to visit your friends, you go there to visit Disneyland.
On the other hand, over the past 26 years, how much down time have they had compared to us? We may have had sections of our sites down briefly, or limited access to members only during transitions, upgrades, or security threats, but we've never been down entirely in 26 years. Even Google & Yahoo can't make that claim. So as odd as the system seems to an outsider, it works efficiently, securely, & reliably.
In it's current form I can load the database from here onto any fresh clean installation of SMF forums, or with simple conversion to any PHPBB, or Vbulletin forum with all the stories, & memberships intact in under an hour... except very long parts may get corrupted by breaking them down to smaller packets so they upload to the database server.
I find I get no corruption or problems if I keep the entire part in 1 big data packet. But if it's too big, the database transfer is rejected due to oversized packets.
Web servers also don't stay the same over mere months, or change their policies, raise their prices, fall out of favor, or just decide they don't want sissy sites or stories on their equipment anymore. I may have to jump to another server at a drop of the hat. Stories has jumped between 3 different servers in the past year & had to be rebooted from a backup database several times in just 2020. Most of the time you don't notice it because it's quick & seamless.
As for readability, I get lots of compliments on our nice, sharp, high-contrast text. It compares better than most since the trend these days is for grey or pale grey text on white... incredibly hard to read. And staring down a bright white lit up screen with dark text very long has already proven to cause a lot of eyestrain. My eyes hurt, get sore, & start to loose focus if I spend a lot of time on Facebook. Most of us don't have that problem here. The background is very dark so shouldn't interfere at all with the pure bright white text (not colored).
If it isn't, you may have your browser, DPI, or screen calibration set wrong.
The design gives a uniqueness to us, & gives me a chance to express some artistic flare, creativity, or imagination beyond just a boring grey, blue, & white generic BBS, plain FMania, or totally dark DeviantArt. I have to see these every day for 26 years. I need them to be pretty.
Facebook, many browsers, & other sites came out with night or dark mode so the screen doesn't overwhelm the room or your eyes in the evenings & mornings. But with the body of the text in pure white here, it can easily be read outdoors in bright light too.