Okay...
Why can't you make a bullpup big game rifle, exactly? It seems to me there's a certain crowd that just disapproves of bullpups, and will come up with all sorts of things to reinforce their notion.
Bullpups will always have bad triggers, for one. Making a bullpup have what is considered a good trigger might be a bit more involved, but I doubt it's an engineering impossibility. I'll bet
THIS had a pretty decent trigger, and
THIS probably does too.
There's no reason you can't make a bullpup firing any cartridge from .22LR to .50BMG. A bullpup won't necessarily be any lighter than a conventional rifle, just shorter for a given barrel length. Hell, you can even put a wooden stock on it if you want.
As for the "not being able to make powerful rifles" argument, I'll see Taliv's .50 Browning and raise HIM a
15.2mm Steyr APFSDS.
That's a three hundred and eight grain tungsten flechette at four thousand, seven hundred and fifty feet per second. Not QUITE a bullpup, but the action IS by your face, not in front of it.
And
HERE is a pretty cool Russian design firing a special subsonic 12.7mm round. It's a 910 grain bullet at just under a thousand feet per second. (And the bullet is solid bronze, oddly enough.)
And if you're not convinced,
HERE is a 20mm Bullpup anti-materiel rifle.
In any case, the argument that you can't make a bullpup safe to use with powerful cartridges is nonsense. If you're really worried about it, all you need to do is add a layer of steel to the underside of the cheekpad. It would be enough to deflect the blast out the weaker side of the action in the event of a kaboom. Frankly, I don't think it'd be necessary.
I don't think the shoulder-switching thing is an issue anymore, either. FN proved you can make an ambidextrious bullpup. And if you get into the possibility of using caseless ammunition, the ejection point is moot anyway.
All I'm saying is, you don't have to like bullpups. They're certainly not common in the US, so if you can't stand being around them this is a good place to be. But saying that they won't work is a fallacy, because they can function as well as any other firearm.