"Commodore BASIC and Atari BASIC both had on screen editors where you could LIST your program on the screen and cursor up and down and change the code and when you pressed ENTER on a line, that line was re-entered into the program."
My first employer (now known as GE Aviation) back in the 80s had mainframes from Honeywell that worked the same way. GE Aviation had started with GE computers, had sold off its mainframe GE business to Honeywell in the early 60s and GE Aviation continued to use derivative models for decades later.
After listing a bunch of code (Fortran, of course) onto the screen, you'd cursor around making your changes, then hit the F1 key, which was programmed to send the screen one line at a time. God forbid that you'd spend a serious amount of time making those changes, because the modem (yep, we used a modem WITHIN the company) would time out, you'd disconnect and lose all your work.
I forget how we edited non-code files, but I guess that they must have had line numbers too.
Fortunately, we had systems other than the Honeywells that we could use (just about everything you could name), but most of the older internally developed software resided on the Honeywells.
You're probably aware of all of the following, but no one else has mentioned it, so I thought I'd add it.
I'm a mechanical engineer that uses a variety of commercial software, as well as developing extensions for that software via the software's API, and also developing standalone software for our own internal purposes.
A lot of that commercial software that we use has a very long history, sometimes even starting way back in the mainframe days. It's expensive stuff, costing $100k or more per user.
A couple of programs follow the pure subscription model, and none of them follow the pay once to 'own', with a period of maintenance built into the purchase price.
What most of them follow is what I'll call a purchase and maintain model. The user purchases the software, then pays a yearly maintenance fee (typically 1/8 the purchase price) that provides regular updates and support (via phone and web portal) for as long as the maintenance fees are paid.
If the user stops paying maintenance, the then current version continues to be usable indefinitely, but the updates and support stop.
If the user decides to stop paying maintenance for a period of time, then wants to restart it, the user has to either 1) make all the maintenance back payments all the way back to when the payments stopped, or 2) , repurchase the software.
I don't know if any of that is useful to you, but it seems like you were trying to gather ideas on business models. I've spoken to some of the software companies that use this model, and they like it. They use it to make a rough internal allocation of resources/funds. The income from the maintenance fees covers the staff directly supporting end users, plus bug fixes. The income from the initial purchases funds strategic and tactical development of new functionally.
A final note: all of this often uses a floating license model with a central licensing server within the end users' controlling the number of simultaneous users (though a license file tied to particular computer(s) can be installed locally as an alternative). The users' company pays the yearly maintenance fee up front to get a licencing file that authorizes usage for the next 12 months. I don't see how this could work without running a licencing server, or across the internet, and that be more complicated than anything you want to consider.
My first employer (now known as GE Aviation) back in the 80s had mainframes from Honeywell that worked the same way. GE Aviation had started with GE computers, had sold off its mainframe GE business to Honeywell in the early 60s and GE Aviation continued to use derivative models for decades later.
After listing a bunch of code (Fortran, of course) onto the screen, you'd cursor around making your changes, then hit the F1 key, which was programmed to send the screen one line at a time. God forbid that you'd spend a serious amount of time making those changes, because the modem (yep, we used a modem WITHIN the company) would time out, you'd disconnect and lose all your work.
I forget how we edited non-code files, but I guess that they must have had line numbers too.
Fortunately, we had systems other than the Honeywells that we could use (just about everything you could name), but most of the older internally developed software resided on the Honeywells.