The IC can go from monolithic to modular if they switched from the subnet model to every cannister being a blockchain with programmable security requirements. I dislike how the IC prescribes the speed/security tradeoff to developers, not letting themselves choose.
Really the only function of the IC should be to co-ordinate and serve high spec nodes to developers looking to leverage blockchain consensus. As it currently stands the IC prescribes a compute environment to developers, and if their dapp does not function well within the 13~ node subnet environment they are essentially out of luck. There are lots of applications that require more than 13 nodes for security (defi) and likely lots more that require less than 13 nodes (non-critical data). I posted a thread about this but got no replies.
This model also opens up more opportunities for dapps. Consider the idea of an online videogame that could create a single cannister and assign a node count of 1 to serve as the server in an online match (real time videogames cannot process inputs through consensus) that then publishes the results to another cannister of size 10~ that stores historic game data. Something like this is completley infeasible with the IC’s current model.