I think that's way too large of an estimate. As long as we could continue to access records of how we did things, and the planet had sufficient relevant resources, I bet we could bootstrap ourselves from having only primitive mechanical tools to today's tech in a few generations. Again, that's assuming the planet is relatively hospitable and has the correct resources available.
Longer term though.. is it practically/economically feasible to build and run a chip fab capable of building modern ARM CPUs for the needs of 10,000 people? What about the rest of the manufacturing chain for these sorts of devices? Or is the only reason we can buy a smartphone today for a few hundred dollars because of the economies of scale of building tens of millions of them on a 2 year replacement cycle?
And I'm not sure 100,000 people is enough. You need the right people in the right place at the right time.