The Il-76 production line is not running at full capacity right now. It could be producing 2x or 3x the aircraft per year.Not sure what airshow is this, but that sign can't be mistaken. Looks like the WS-20 engined Y-20 will be available for export.
Not many competition in this space too, C-17 is out of production, Il-76 production rate is way too low, Kawasaki C-2 is almost half the size.
The reason they aren't producing it faster is lack of orders.
There might be impacts due to capacity constraints in engine manufacturing however. Since the factory which makes them is going to be incredibly busy making engines for the MC-21 in like 2 years time.