Doesn't it seem wasteful that 18f spent all that time on the standards, instead of maybe a guide/theme on how Gov't sites should adapt, already open-sourced (bootstrap), frameworks?
Take a look at https://github.com/18F/web-design-standards/blob/staging/LIC... and count the number of existing open-source projects which they're re-using. This looks to me like an experienced team who did their homework to assess how much flexibility and control they needed and reused as much open-source as possible while still meeting their other requirements.
Frameworks and standards like that are more often needed because there's a huge ecosystem of custom, proprietary libraries and frameworks that also exists within government. Previous attempts to try to release standards that only address specific frameworks that are popular within the open source world may only ever apply for 20% or so of federal agencies. There's even "agency-specific" forks of open source software that looks nothing like what they were based upon now. But really, you have tons and tons of different frameworks out there that have wasted taxpayer money delivering nothing material in value except "the government owns its IP" meaning "it avoids political / legal problems." See https://github.com/ozoneplatform/owf-framework for an example
Second of all, nothing precludes them from releasing standards-compliant variants of frameworks after the higher level standards are complete.