I think with the number of used equipment of your choice out there.
And other radios still being made. We should be good for the foreseeable future.
But nothing lasts forever.
Jeff and I have become the depository for Multiplex radios, and Kevin Mac, and Don O for Futaba 9Z's.
As much as I love my Multiplex its hard to beat the bang for the buck of the 9Z.
You can get them for chump change compared to the cost new and it will do 2.4- 75- 72- and 50 MHZ with only a plug in deck change.
Granted it will probably weigh more than your submarine.
But that is why they invented neck straps.
The best advice I have weather it be a new or used system is buy two.
I bought 5 but I am crazy.