I always saw Abandonware as a necessary evil, flagrant copyright violation when the copyright holder has zero interest on their property, but GOG and such are a good alternative. Not only the games are sold at reasonable prices and put under rather regular sales, but avoiding DRM does make sharing significantly easier.
I am curious to know what you are talking about. I've never heard Bethesda getting money from the DoD. And I've found nothing, since all search results are mixed with info about the military base in the city called Bethesda.
Bohemia Interactive created a division, Bohemia Interactive Simulations, to handle the military training software, which has worked with other NATO countries.
But from the Wikipedia page, the division has been bought by an equity firm, The Riverside Company, in 2013. So Bohemia Interactive doesn't deal anymore with the military, even if they might still have contact in the military, since they have developed military simulations.
Even those impose centralized control on there software though:
I assume you mean Bohemia Interactive, who make ARMA?
I make the same mistake.
Company like Bethesda or CDProjekt are showing that having one long running game can work too. (Bethesda is a bit strange due to their military contracts but still).
CDProjekt are even more interesting because they are behind GOG.com . Which spend time making old game playable on recent PC, but sell them for a price when they were abandonware before. Most of the time without DRM. The interesting part is they do make money through it. Which shows that you can keep a small but longterm income from your backcatalogue.
At the same time, they are making abandonware harder to support through copyright exception since copyright holders now make money again ...