But seriously guys, I cannot imagine that any scientist conducts research in such a random way as it is done in Stellaris. You just don't go and await what the day brings for you. Scientists get specific tasks and then they work on them.
Imagine you are head of your state and need a new or improved ship model or a new weapon. Naturally, you would go to your scientists and tell them to research a new ship or weapon technology, wouldn't you? I don't see any way the scientists answer would be something like: "Well Sir, we cannot research the new ship, because at the moment, we do only have this new food building and a method for even faster research available. You might ask again in 100 months."
How about: You're the head of state and you ask your researchers to come up with designs for a battleship and they say "Sorry, we don't know how to build a ship any bigger than our cruisers, and we don't currently have any ideas for how to solve the various structural issues that keep us from making anything bigger. But we do have a proposal from a guy who has an idea for how to make a more efficient food processing plant, and a proposal for a new mineral extraction process, and a proposal for a better plasma gun. Those are the only ideas our scientists have at this time. Which one would you like us to work on? Maybe we'll have a better idea on how to make bigger ships later on, but no matter how much we try right now, bigger ships keep folding up like oragami when we turn on the engines. We can't do much until someone comes up with a new idea." That's how the current system works, and it makes a certain amount of sense. Kinda. It's not perfect, but any system that only allows you to research one tech at a time is going to be unrealistic. At least we get to research techs from 3 different fields (physics, society and engineering) at a time.
It's not like you could have researched how to make an atomic bomb during World War I. No one had any clue how to do it then, and no matter how much money you might have thrown at it, you couldn't have done it. The research project simply wasn't available. But 30 years later, a few bright folks had come up with new ideas, and suddenly it was on the list.
What I have a problem with is that I can know that it's possible to make an ecumenopilis, which requires the Arcology Project ascendence perk, and for some reason I can know that I first have to have Anti-Gravity Engineering technology to get the perk, but I have no way of knowing what I have to do to get that tech. It's certainly not obvious that I first have to get the Weather Control Systems tech.
And as I write this, I can't just go check the wiki, because the wiki currently has no info on the Anti-Gravity Engineering tech. This kind of info needs to be accessible within the game. Maybe an actual "tree" representation isn't needed, but some way to find out what tech is a prerequisite for another is.
As has been pointed out, there is no guarantee that Anti-Gravity Engineering (hereafter, AGE) will show up as a research option as soon as I finish Weather Control Systems (WCS), but it
is guaranteed that AGE
won't ever show up until I have finished WCS. And if I don't know that WCS is required, I could waste a whole lot of time researching more useful sounding techs and wondering why I never have AGE available to research.
I've found this stuff called Dark Matter, and I know that I need the Dark Matter Drawing tech to use it. But I keep waiting and waiting for it to show up in my list so I can research it. What? You mean I have to learn
sensor techs to make it available? WTF? How should I have known that? (At least that one is on the wiki)
It's a grand strategy game. We should have the info available that is required to plan and execute our strategies.