Comment by tgtweak

I was thinking about it the other day when reading the original article, and this was the only plausible (and defensible) cause for it not being addressed:

When GTA online was released 7 years ago in 2013, the list of DLC items was probably much shorter, and grew over time. The performance issue is exponentially aggravated with list-length. The list growth was probably bell-curve shaped over the lifetime of the game.

This has an interesting dynamic when it comes to perceived performance:

In the beginning, on consoles and PCs - it was already a pretty long load time, but would have been 90s or so on an average gaming PC (I remember this from the early days playing it, on a modest gaming PC with an FX-8150 cpu). This is long, but tolerable for a game of this size. I'm certain that early complaints that it was sluggish to load were profiled and looked at, and at the time it wasn't a 4 minute ordeal to load the json and probably represented a fraction of the CPU time it takes today - not standing out as obviously as in OPs guerilla profiling. Devs put a pin in it and say "this is netcode related, it is what it is"

Over time, the list gets longer, the loading time takes more cycles, BUT, PCs are getting progressively faster year over year as well, with many of those improvements happening at the instruction-level - optimizing for things like, surprise, string scanning. Two console generations are released since, masking the problem on that side. For comparison sake, I just checked and I can load GTA online in about 75s on my Ryzen 3900x. This cpu is probably 4-6x faster in single core performance than the 8150 for most workloads. Again, it's slow but tolerable and by this time it's "yeah GTA online is just a big game and takes a while to load, it's always been that way". Complacency is the enemy of improvement, and things that regress slowly over time are hard for us to notice in general.

Don't take this as a "this is fine" comment, but instead the only reasonable justification I can think of as to why it might have flown under the radar all these years.