Do we still need bomber aircraft when we can launch extremely accurate missiles from practically anywhere? Even if they are not "stealth" a hyper-sonic missile is almost impossible to stop.
The B-21 is a fixed cost that is ready to go: just 'add water' (munitions) and you can have a higher pace of operations as long as you can feed the machine (B-21).
Still, strategic bombers add capability that drones/missiles don't. In particular, eyes on the target still haven't been deprecated by remote optics in drones and missiles can't loiter.
[1] https://www.thestreet.com/phildavis/stocks-options/the-penta...
https://nationalinterest.org/blog/reboot/stealth-down-how-se...
And given that Israel has been running around Syria with their F-35s being undetected by the S-400 not sure how much confidence anyone should have in Russian claims.
Also, Russia has already delivered some S-500s into service. Their supply chains might be strained, but they are still functioning & mostly domestic sourced.
You don't deploy billions of dollars worth of infrastructure in Syria just to leave it switched off.
Stealth is a not a cloaking device. It's a <1 multiplier on enemy radar range. If you get close enough, you will still be targeted. But combined with sufficient standoff range on your weapons, stealth enables hitting your target before they can hit you.
https://seapowermagazine.org/vice-adm-hill-mda-pushes-space-...
2. Because they can change course at high speed, a slower intercept weapon will miss if it counts on predicting the flight path to intercept. At present this is how most surface to air and point defense weapons systems work.
3. Point defense systems may not be able to react fast enough to stop a hypersonic.
4. More kinetic damage. This is significant for ships.
Are there bunker busting missiles, or is a bomb needed to go down vertically to penetrate?
Yes. Missiles are expensive and can't be reused.
In all likelihood this craft will be a command and control center. Can target missiles and control drones.
Lots of claims of both but no actual evidence.
So it's impossible to gauge the accuracy of anything let alone the rarely seen Kinzhal missiles.
Nothing in the Ukraine fits this description. Those are ordinary ballistic missiles, which naturally have hypersonic ballistic re-entry. There is nothing interesting about that, we've had it for 70+ years now.
Also consider that russia's Kinzhal can go about mach 4-5. That sounds pretty bad, until you realize that good old ICBMs re-enter from space and travel in atmosphere somewhere between mach 15 and 20.
Fast missiles like Kinzhal are not new at all. As far back as the 60s the USA had the Sprint and Nike which could accelerate from the ground to mach 10 in seconds and would glow white hot from heating. Even maneuverable glide vehicles aren't new, the Pershing II could perform limited course changes during descent back in the early 80s. Yes, fast missiles are scary, but they're not in the same class as true air-breathing hypersonic weapons.
https://en.wikipedia.org/wiki/Nike_Zeus
(b) may not be necessary: hitting military bases, and munition and fuel stores, neither of which are moving targets, is a useful capability.