But there are many robust and capable handheld radios in widespread use. Insisting that ours be designed to order would seem to be a good example of wasteful procurement.
Agreed, but as long as one differentiates between Commercial and Military off the shelf. Another factor is interoperability. And Joe Bloggs Backstreet Comms Ltd isn't likely to understand a typical MoD SIMOPS, Transec or Comsec requirement, never mind have the wherewithal to implement a cunning plan to demonstrate interoperability with various allies. (Not that many co-operate with us, or that we ever seek true interoperability!) A good example of a perfectly valid reason for a made to measure radio is the 1980s multi-mode fitted to RN Sea Kings, Lynx and Merlins. (And Nimrod R after the RAF nicked them). Eye-wateringly expensive due to the harmonic rejection spec and non-standard frequencies. Most companies would laugh at the former.