Bank boss bonuses?

Source: Today, 16/2/9, p.B1
Headline: The big bonus debate

Quote1:
From Britain to the US and France, political leaders are clamping down on the bankers' bonus culture, which has been singled out as a cause of the financial crisis. ... However, taking too tough a line with banks could have unintended consequences for taxpayers, according to academics and insiders, who say the risks include banks losing their best staff and their share prices falling even lower to the dismay of the taxpayer ultimately.

Comment1:
Here is the objectors' argument:

Premiss1: If (cap bonus), then (lose best staff)
Premiss2: If (lose best staff), then (share price fall)
Premiss3: If (share price fall), then (taxpayer dismay)
Premiss4: Reject (taxpayer dismay)
Conclusion: Hence, reject (cap bonus)

This is a Modus Tollens rollback. It is a valid argument structure. The only way this argument can fail is if any premiss is false.

Quote2:
Senate Banking Committee chairman Christopher Dodd ... dismissed such fears. ... "The current job market should deter employees from leaving, and if they do, there are many qualified replacements."

Comment2:
"The current ... from leaving" rebuts Premiss1, by asserting that a cap is not sufficient to result in "lose best staff". There is another factor at play, namely "current job market". "If they do ... replacements" rebuts Premiss2, by asserting that lost staff will be replaced by qualified people, and hence that share prices will not fall due to reduction in qualified staff. These two rebuttals block the objectors' argument.