Doug started this thread with his observation that ex/vi was huge compared to other editors. i.e. value: small simple easy to understand (Rob's old "cat -v considered harmful" argument if you will). The BSD argument had always been: "the new stuff is handy." The emacs crew tends to take a similar stand. I probably don't go quite as far as Rob, but I certainly lean in that direction. I generally would rather something small and new that solves a different (set of) problem(s), then adding yet another wart on to an older program, particularly when you change the base functionality - which is my vi vs. vim complaint. [i.e. 'partial credit' does not cut it].
To me, another good example is 'more', 'less' and 'pg'. Eric Schienbrood wrote the original more(ucb) to try to duplicate the ITS functionality (he wrote it for the PDP-11/70 in Cory Hall BTW - Ernie did not exist and 4.1BSD was a few years in the future - so small an simple of a huge value). It went out in the BSD tapes, people loved it and were happy. It solved a problem as we had it. Life was good. Frankly, other than NIH, I'm not sure why the folks at AT&T decided to create pg a few years later since more was already in the wild, but at least it was a different program (Mary Ann's story of vi vs. se if probably in the same vein). But because of that behavior, if someone like me came to an AT&T based system with only pg installed, so those of us that liked/were used to more(ucb) could install it and life was good. Note pg was/is different in functionality, it's similar, but not finger compatible.
But other folks seem to have thought neither was 'good enough' -- thus later less(gnu) was created adding a ton of new functionality to Eric's program. The facts are clear, some (ney many) people >>love<< that new functionality, like going backward. I >>personally<< rarely care/need for it, Eric's program was (is) good enough for me. Like Doug's observation of ed vs. ex/vi; less is huge compared to the original more (or pg for that matter). But if you value the new features, I suspect you might think that's not an issue. Thanks to Moore's law, the size in this case probably does not matter too much (other than introducing new bugs). At least, when folks wrote did Gnu's less, the basic more(ucb) behavior was left along and if you set PAGER=more less(gnu) pretty much works as I expect it too. So I now don't bring Eric's program with me, the same way Bakul describes installing nvi on new systems (an activiity I also do).
Back to vi vs. nvi vs. vim et. al. Frankly, in my own case, I do >>occaisonally<< use split screens, but frankly, I can get most of the same from having a window manager, different iterm2 windows and cut/paste. So even that extension to nvi, is of limited value to me. vim just keeps adding more and more cruft and its even bigger. I personally don't care for the new functionality, and the size of it all is worrisome. What am I buying? That said, if the new features do not hurt me, then I don't really care. I might even use some of the new functionality - hey I run mac OS not v7 or BSD 4.x for my day to day work and I do use the mac window manager, the browser et al, but as I type this message I have 6 other iterm2 windows open with work I am doing in other areas.
Let me take a look at this issue in a different way. I have long been a 'car guy' and like many of those times in my youth spent time and money playing/racing etc. I've always thought electric was a great idea/but there has been nothing for me. Note: As many of you know my work in computers has been in HPC, and I've been lucky to spend a lot of time with my customers, in the auto and aerospace industry (i.e. the current Audi A6 was designed on one of my supercomputer systems). The key point is have tended to follow technology in their area and tend to "in-tune" with a lot of developments. The result, except for my wife's minivan (that she preferred in the years when our kids were small), I've always been a die-hard German-engineered/performance car person. But when Elon announced the Model 3 (like 1/2 the techie world), I put down a deposit and waited.
Well why I was waiting, my techie daughter (who also loves cars), got a chance to drive one. She predicted I would hate it!!! So when my ticket finally came up, I went to drive them. She was right!!! With the Model 3, you get a cool car, but it's about the size of a Corrolla. Coming from Germans cars for the last 35 years, the concept of spending $60K US in practice for a Corrolla just did not do it for me. I ended up ordering the current Unixmobile, my beloved Tesla Model S/P100D.
The truth is, I paid a lot of money for it but I value what I got for my money. A number of people don't think it's worth it. I get that, but I'm still happy with what I have. Will there someday be a $20K electric car like my Model S? While I think electric cars will get there (I point out the same price curve on technology such microwave ovens from the 1970so today), but I actually doubt that there will be a $20K electric vehicle like my Model S.
The reason is that to sell this car because it as to be expensive for technology-based reasons, so Tesla had to add a lot of 'luxury' features like other cars in the class, other sports cars, Mercedes, et al. As they removed them (i.e. the Model 3) you still get a cool car, but it's not at all the same as the Model S. So the point is, if I wanted an electric car, I had to choose between a performance/luxury vs. size/functionality. I realized I valued the former (and still do), but I understand not everyone does or will.
Coming back to our topic, I really don't think this is a 'get my lawn' issue as much, as asking someone what they really value/what they really need. If you place a high-value you something, you will argue that its best; if it has little value you will not.