Well, the design goal is for players to not strategize their research, ins't it?
Eh.... within limits yes it is. For one thing thats why scientists have traits, and all techs have tech weights.
A number of other examples include:
a. A number of techs having an increased chance to show up when you have certain traditions taken, supremacy grants increased ship & component weights for instance.
b. A small number of techs have increased weights for certain Ethic types
c. Gateway techs, like Exoskeletons, can be ignored to safely remove an entire sub-branch of techs from your pool
d. Researching debris, of course, either to get techs, or to intentionally remove them from the pool
e. A number of techs are not only unlocked by Ascension Perks, but a number of other techs have an increased weight if you've taken certain Perks
f. Starbase upgrade techs for instance are weighted based on the number of upgraded starbases of the previous type you have
g. Upgrades of buildings that use strategic resources are generally gated behind whether or not you have access to that resource
h. Certain techs are actually weighted based on your Civics, or even excluded
I. Certain techs are weighted, or even excluded, based on your policies
j. Certain techs are weighted by what megastructures you have
k. Certain techs are even weighted by the level of the scientist you have doing the research
l. Certain techs are weighted by how many planets you own
m. There are techs weighted or excluded based on your pop rights, slave techs being an obvious example.
n. There are techs weighted by your active country modifiers, like Curator Insight
o. There are of course a number of techs that you can most easily get from anomalies, and even ones you can specifically fish by completing anomalies in a certain order or in a certain way. The rare and expensive tech Construction Templates for instance can be easily fished from anomalies if you first research Assembly Pattern
So.... I really cant agree with your assertion. Tons of effort has been specifically put into making research strategizable.