you mustn't understand how companies deal with their capital expenditures, and replacement costs of infrastructure.
a company is going to replace network gear typically every 5 years or so. same company may replace servers every 3 years depending on need/workload.
those replacements are typically spelled out 6 months prior to the year in which they are replaced, and the new cost is put into the capex. capex goes through approvals, and typically gets a nice little chop because IT wants to add/replace too much. capex goes back to IT Director, who plays with the numbers, removes a few upgrades, sends capex upward for approval.
once approved, engineers are going to replace gear that will benefit the organization for the next 3 to 5 years, where the cycle will repeat itself. and because the spend is kept artificially low, only the most deserving pieces get the money.
why would engineers think to deal with IPv6 if IPv4 is not a real pressing issue when upgrading? the pressing issue is going to be the pressure to lower latency, remove bottlenecks, and scale bandwidth. when your boss(es) are breathing down your neck because you dropped 500K on some new gear, the last thing you're thinking about is solving the internet's (someone else's) problems.