I like these
gedankenexperiment type threads
Performance can be increased by one of two ways - (1) increase the rate at which work gets done (more clocks per second), or (2) increase the amount of work that gets done per clock.
Increasing the amount of work that gets done per clock can be done by complicating the compute model itself - move beyond binary.
Ternary (3-bit states), analog (spectrum of states), quantum, etc.
Making the compute models more complicated (and scaling that complication ever more so going forward) is one way to get more work done per clock cycle within an existing physical circuit mechanism (transistors of silicon, etc).
Keeping the same compute model, binary logic, and just pushing the number of cycles per second that transpire can continue for a ridiculous period of time yet. The current method of getting more cycles is by way of making traditional circuit components cycle faster and faster.
This clockspeed scaling correlates with physical scaling in real-space.
But scaling can work in something called inverse-space (aka k-space or
reciprocal space).
A reciprocal lattice scales inversely proportional to the existing crystal lattice.
Seperately you can create
superlattices of ever more sophisticated electronic structures you can create effective switching speeds that exist in a virtual sense, making your compute topology function in a meta-physical domain.
And of course you could go for the ultimate and make scalable reciprocal lattices of superlattices for the ultimate in pushing the physics of the meta-physical devices with which you use for your ternary, or analog, or quantum computing models.
Economics really is the limit. We can push on meta-physical reciprocal lattices for hundreds of years if we wanted (since it scales inversely in real-space, circuits become physically larger so no physical scaling limits).
The physics for all this stuff is already worked out, much the same way as binary computing was worked out long before the invention of the transistor.
What doesn't exist yet is an infrastructure for making it commercially feasible and economically viable. The same as could be said of the transistor when it was first conceived.
But there will be a way, provided there is a will.