Strongly disagree on your mold idea. LEGO’s stringent quality control is one of the things that makes it great. My childhood legos are all at my parents house, and my kids love to play with them when we visit. They still work perfectly 30 years later.
That level of quality is impossible with your local library mold idea. It would inevitably churn out low quality bricks due to (1) bad inputs and (2) molds not being replaced regularly for wear and tear, which would be accelerated due to (1).
You can’t just throw whatever plastic trash you have into a machine and expect it to produce good or even useable bricks.
In grad school I knew a guy who was reeeeally into the idea of building benches out of reused plastic and cob. The basic design was plastic bottles stuffed with plastic bags acting as bricks, which are then cemented together with cob.
Cleaning the bottles and bags was incredibly difficult, even at the scale needed for a single bench. Just a massive amount of effort... The difficulty was that any residual bacteria would multiply and off-gas, eventually causing structural problems.
Likewise, I expect the biggest problem for a home-LEGO-recycler would be dealing with the many random impurities in the input stream.
First, they need the LLM instructions AI thingy to look at your pieces and instantly come up with inspiration. Gamify that.
But they need to pull a KIA in that they hired the young designers away from GM and gave them some room.
There needs to be a revolution in LEGO with the following:
A device which is communally owned - at a Library or an Elementary School.
Throw in plastic bottles and plastic waste.
It molds LEGO bricks.
And you can program different sets.
And kids can create sets and have the device spit out the bricks for that set they designed.