Before you speculate and jump to conclusions, let's put things in to perspective.
At this current time, all individuals who are involved with modding GTA5 publicly, have to be on their toes due to the recent legal issues.
Any software that is dependent on a larger software will always be under the mercy of that larger software.
Any person developing this software purely for the sake of the software and community, should be appreciated.
That being said, worst case scenario, Alexander abandons ScriptHook. Does this mean SH will be gone forever? Hell to the no.
The reason no one else is developing a hook (besides it being very difficult) is because Alex already did. A damn good one if I might add.
If that hook would stop being developed, you bet your ass someone else will make one. It's not a matter of if, but a matter of when.
That when could be a long time, but the fact remains, SH and in my opinion OpenIV won't die so easily. There are people who will keep it alive and will maintain it.
Seeing everybody over react is a classic case of dependent software. It happens in nearly all third party "private" development tools.
When OdinMS was shut down, every body cried and said MS private servers would die. That was how many years ago? And look, the original OdinMS source still exists, and many servers are alive.
Also, anybody who says "JUST MAKE IT OPEN SOURCE" has no idea the amount of time and work it takes to create this kind of software. Not only that, but to make it stable and public...
Please do not under appreciate the labor that must be endured to get these mods and beautiful tools working.
Be patient and appreciate the fact people make these tools available for free. In fact, what you SHOULD be doing is supporting the creators of OpenIV and Scripthook in their time of need.
They are going through a lot of trouble as you read this right now, all because you want to roleplay the Hulk in GTA5.