Au contraire. For workers with similar qualifications, a fall in manufacturing wages probably means downward pressure on service wages. Conversely, service workers have more bargaining power if there is an ample mfg sector to which to move.
Secondly, lower mfg wages put more of an implicit tax burden on service workers, since they have fewer better-paid peers to shoulder the tax burden. There is also some prospect of loss on the public service side, since lower wages means less taxable resources, insofar as workers tend to live in common local jurisdictions. Less mfg'ing also leaches tax capacity from state and local govs because their retail sales taxes are less able to tax services than goods.
If mfg workers are easier to unionize, there is a wage bargaining effect in that dimension as well.
Having said all this, I do agree that it is possible to over-emphasize trade, and we are testing those limits at EPI every day.
mbs