Re: Well you sound smart.
" I'm not aware of any feeds into my dc that are over 100. Still too finicky, and the termination equipment is outrageously expensive at 100."
Most of the stuff I see going in now is 200Gb/s wavelengths and has been for a couple of years - 100G is actually getting pulled out and replaced by 200G by one of my customers - transponders occupy the same or less number of slots, power consumption is less and as a bonus you get twice the data rate per wavelength. I guess the difference is that I work with the same types of DWDM kit that goes on the end of submarine cables, not what goes into data centres - although that said, we do sell routers that will take 400G interfaces and we do now have DWDM transponders that can do 400G coming on to the market.
"Depending in what you can put down on the ocean floor as a repeater, every 30 klicks,"
Or maybe amplifiers rather repeaters, which are limited to their original design rate and protocol - the spacing is usually a compromise between the end-of-life capacity requirement from the customer and how to achieve that with the minimum number of amplifiers. Every amplifier requires 50 volts across it, so a long cable can require as much as 25kV to be supplied, which imposes problems of its own when moving this stuff around.
"It's not like the coastal facility is a data center, it's just a switch/repeater to some inland dc."
I've done work in several landing stations - they are more "just" a switch/repeater and have all included a variety of systems for breaking out sub-rate data streams for the various cable customers in addition to the basic cable terminal equipment - ie.the large and complex power feeding equipment, some form of optical routing/DWDM kit to terminate the fibres and the crucial station earth (just in case the sea earth fails for some reason). At least two of them have included one or more major PSTN switches in addition to data switching/routing kit - months to move, years to plan.