I once worked on a project (US DOD) that was basically a conversion from monolith to SOA. The contractors did, in fact, fight tooth and nail to keep it from happening because it would reduce their apparent value and necessity. USAF totally fucked up the management of it (at the time I was involved), other services had similar projects which had much better transitions. And for them it substantially reduced costs and decreased time-to-feature. USAF just seems dead set on using the old block release style (big bang releases every 12-60 months) which was at odds with the attempted conversion and helped the contractors persist their miserably awful architecture that practically ensured another few billion in revenue for them.