Not at the cost of ~

There has been a long discussion on the ETJ forum (see for example here) about whether or not the distinction between English gerunds and present participles is arbitrary. I've been argue that it is, because gerunds do not in fact consistently act like nouns. This is the position taken in the Cambridge Grammar of the English Language.

Most of the arguments have been based on syntactical properties, but we coincidentally came across a construction that shows another way in which gerunds are unlike nouns. Where one writer had suggested that it would be nice to come to some consensus, I replied "not at the cost of internal inconsistency". The other writer said, "don't you mean at the cost of internal consistency?"

A google search shows that the normal way to express what I wanted to say would indeed have been "not at the cost of internal consistency." In other words where of is followed by a noun, the normal expression is "not at the cost of (good thing)."

• Our readers enjoy interesting words, but not at the cost of readability.
• Individual autonomy is attained but not at the cost of relatedness with close others
• Defence deals not at the cost of transparency
• 6200 ftServer offers solid fault-tolerance--but not at the cost of performance
• Most Pittsburghers want a more civil society, but not at the cost of fairness.
• Water-sharing pact not at the cost of fraternal ties

On the other hand, where of is followed by a gerund, the normal expression is "not at the cost of (bad thing)."

• We wanted to grow, but not at the cost of sacrificing quality.
• Healthcare systems need policies to keep costs down so that we can afford our insurance premiums, but not at the cost of losing our basic rights.
• the respondents said they wanted power -- but not at the cost of losing respect
• benefits of xenotransplantation realized, but not at the cost of compromising public welfare.
• to develop public programmes that would address the interests of their varied audiences, but not at the cost of ignoring their primary audience.