A Different X Each Time

I would take warnings that antibiotic X is last recourse and bacteria are becoming resistant to it more seriously if it weren't a different X each time.

I would take warnings that corporation X is eliminating all competition more seriously if it weren't a different X each time.

I would take warnings that nation X is overtaking capitalist America more seriously if it weren't a different X each time.

I would take warnings about the dangers of immigrant group X more seriously if it weren't a different X each time.