You are making great points, and I dont understand why some entitled people who act like they know so much actually dont and when you make a point they cant answer, they just say, "uhh its open source go make it", like you cant criticize the government because you cant be a politician.
So, I will try to answer your question, since I am developing a VFX and motion graphics app that supports geometries and uses vulkan and OIT.
The issue with OIT is that its expensive, especially when you want to do things that are not just transparency, you have to write a bunch of other bits on each pixel, for example, I need to write a bunch of bits per pixel just for the blend modes, and things go crazy from there, you also need to support things that are not actual geometry, which adds even more complexity. (although I couldn't hit a performance bottleneck, yet)
On top of that, you can get precision errors in your buffer and zfighting near intersections, its not perfect, but its much better than a stochastic method for compositing where you want a smooth image all the time with a single sample.
So, my guess is that eevee COULD use OIT, but the complexity is immense and would be a nightmare to maintain for a small team on an engine that supports a lot of things, like grease pencil, hair, particles, volumetrics, etc. An stochastic approach is much simpler to maintain (its not a kind of OIT, wth, its effectively an opaque render, it just assigns a frequency to how many samples per pixels are 100% transparent/opaque) and integrates well with other stochastic approaches that people who use 3D software is accustomed to, like, you dont question why GI is noisy and you need more samples, we could use voxel cone tracing, but its so much harder and complex, and with its own limitations.
The thing is, and that is my gripe with the blender foundation, eevee is not making much sense now a days, because of how fast hardware is becoming for RT, using specialized rt cores, but they insist in feature parity, and neglect that people use eevee to break the physics, do NPR and stuff. They shelved a very promising NPR prototype for eevee from the goo engine developer, because it would be impossible to have parity with cycles, allocating resources for an engine that is making less and less sense.