The only people who want the open office are the people who either don't want to pay for cubicles, or want to cram more people into a space (worker density) than a cube farm will allow.
The main problem with running 10,000 cores is partitioning your program so that inter-core communication can happen effectively.
You could have several very large thread pools, each performing a different task in a processing pipeline.
You could set up a big SIMD system. Bu didn't the Connection Machine already do this, to the tune of 64k cores?
Maybe you're trying to figure out how to apply the model in a large distributed system where "core" is actually some cloud compute instance. You're back to devising effective ways to communicate with all your cores.
In the end, massively parallel processing, beyond generalized horizontal scaling tends to be designed for a particular problem domain. Some problems lend them selves to vectorization, others to SIMD decomposition, others shared-nothing multiprocessing with message passing between cores.
Corporations wanted to be people. People pay income taxes on their revenue, not their profits.