Always need a conventional bomber, if even not for standoff nukes like the B-52; which is always an option. The B-52 can’t get there like the B-1 can.
The author’s analysis is flawed.
The idea that we could undertake a strike with 200 heavy bombers against either Russia or China...without going full-on nuclear...is ludicrous.
Such an event is certain to precipitate strategic nuclear war.
As things move on, things stay the same. We will always need a robust conventional military and be able to fight a two front war yet I believe the military space race is the future.