Sorry for many posts.
I didnt say only. I wou'd probably get 2-3 cons research AT grenades by the time luchs arrive. To kill luchs 5 grenades are needed. So very unlikely kill it no matter what axis player does. Even if it hit the mine and get hit by at grenade it would just retreat get repair.
Guards with sniper and cons are doing relatively ok in that case but without guards everything would fall apart.
If you get out-teched and produce no counter, that's what happens.
I haven't seen all the notes, so I'm not sure where guards are in this patch, but I remember them being slightly overnerfed. Eventually it will be necessary to heavily modify the early game russian vehicle counters.
On the other hand, I think the scenario you provided is an underestimate of the manpower the soviets would have at around 6-8 mins and an overestimate of what OKW would have.