Vendor lineage
BBN - the contractor that built the first network
A research firm won the ARPANET contract, and the packet switch became a product because somebody had to manufacture it.
Bolt Beranek and Newman began in acoustics - the firm was hired to make auditoriums sound right - and ended up building the machine that made packet switching real. Winning the ARPANET Interface Message Processor contract in 1968 turned a funded idea into hardware somebody had to deliver, support and repair, which is a different problem from proving the idea works.
The IMP is the reason a network device is a separate box rather than a function of a host computer. Hosts differed too much to each implement the network directly; putting the logic in its own machine let one interface absorb the difference. Every router since inherits that decision.
BBN also demonstrates something the timeline otherwise lacks: a contractor whose product existed because a customer specified it. Most companies here started with a technology looking for a market. This one started with a market of exactly one, and the technology came out of the requirement.