And let me extend my apologies in name of all the authors of software whose extra features and nice bug-freeness you enjoyed at the terrible cost of going through the gruelling process of having to upgrade your software.
Perhaps all us developers of modern software could get together raise funds so you could get a refurbished pink iMac G3. Before all those pesky Apple people started their code purity fetishist backwards compatibility breaking migration to a BSD+Mach based OSX.
Do keep in mind that modern software as you state are great tools for completed tools but very little options for those that create the tools themselves, IDE's for example but not limited to that concept. This leads to my point:
To paraphrase the OP, maybe some things should not be fucked with for "code purity" in the name of functional purity. If you vehemently disagree, make a better product. Critical mass will replace the failed ideology that ultimately leads to a better technology. All the flame wars in the world won't change this fact and ultimate outcome.
I do understand my comments are inflammatory, and did not expect at all they'd be upvoted more than downvoted, but that seems to be the case.
Your standpoint is the one many in this thread have and I understand the least. This idea that "code purity" and functional purity are different.
The only reason that LaTex can not be improved is that its code is unaccessible. This means its functionality lies rigidly restricted in the 80s. In my opinion, there's nothing functionally pure about 70s/80s software. Back then, functionality followed from hardware restrictions.
There is a reason people pay for software that just works, and will work for the next few years. It's because they're fed up with being the guinea pigs for architecture astronauts and code purity fetishists.
Also, "that means we only have to upgrade..."
Who is "we" here? You? Of course not, you're too busy chasing the next fad, while the rest of us have to repare shit just to make it do again what it aready did before.