Since many specific space junk collision risks have been assessed, why haven't we combined the data and graphed it? The trendlines could be very instructive. Like mapping climate change, the curve can show what individual numbers don't. The [Q&A that drew me in] (https://space.stackexchange.com/a/53876/42283) seems to follow a specific case approach. i.e. someone is a paid to calculate the probability of a specific event - that Part A has an x% chance of being compromised - but the shape of the equation will be the same across all events - so couldn't there be a tool? Users just drop in the inputs and a number pops out? Yes, for vital real world items the specific case work is justifiable, but the ability to draw and extend probability curves relating to size, value, position seems sensible and obvious. What am I missing?
...so couldn't there be a tool?
Actually there are such tools.
Users just drop in the inputs and a number pops out?
It is maybe not such easy but it comes near.
relating to [...] position ...
Because of orbital dynamics, "position" is not so easy, but I assume you are aware of this topic
What am I missing?
You are missing e.g. ESAs "MASTER"-Tool. As far as I know, everything you ask for.
ESA maintains and distributes a number of models for the characterisation of the space debris environment and its future evolution. The Agency's most prominent debris and meteoroid risk assessment tool is called MASTER (Meteoroid and Space Debris Terrestrial Environment Reference). It covers a size regime for debris and micrometeoroids between 1 micrometer and 100 m. The MASTER software can be accessed free of charge via the Space Debris User Portal.