Since no one is talking about it, I assume it isn’t possible to try a “junk shot” like they did earlier, and then concrete it over?
No, if the well head is damaged like everything is pointing to a capping of any type would cause a huge blowout because of the pressures it would create.
They are also saying that there is, or may be, damage to the actual well casing itself -- so, again, if they cap the well in any way it would be a moot point if the well casing failed completely below ground. The Oil pressure would then basically shove the entire well out of the ground and it would be a completely uncontrolled and uncontrollable gusher.
The only capping solution is the relief wells and sealing it from the bottom.
If everything continues to fail then at some point they will run out of containment options, and the ONLY option will be to secure the BOP stack as much as possible to prevent a blow out at the well head itself and let her gush.