Cut any one variant and the other 2 become unaffordable to partner nations. It's a downward spiral as Governments concerned about costs amid economic worries pull the plug (Canada, Italy etc). Fewer orders of A's puts the price up further and the spiral continues.
It's all 3 variants or nothing. Nothing would prob bancrupt LM as their other military platforms drop off, unless T-50 becomes T-38 replacement. Massive job losses politically unacceptable so I see all 3 surviving but with delays to full capability.
UK sucks up the costs long term.