I have been in several business discussions regarding source code in escrow and in all of them they have agreed that having the code released as BSL or eventual

I have been in several business discussions regarding source code in escrow and in all of them they have agreed that having the code released as BSL or eventually Open Source would be ok with them. After all, companies using your software wants just to be sure that they can continue to use it as before if you stop supporting it. For this purpose BSL works perfectly as a default. If they need more, then you make an explicit contract just for them where you give them more rights to the software.