Earlier quoted context omitted.
The ideology just happens to align so well with the interests...
Not really -- most business lobbyists are looking for various forms of corporate welfare. They want special treatment for their business/industry, or barriers to entry that prevent competitors from getting a foothold. Yeah, low regulatory barriers can help a whole industry, but why do you think many big companies lobby in favor of regulations? Big businesses can handle regulations way better than small companies (see…
Just because deregulation doesn't give you a leg up against competitors within your industry doesn't suddenly remove self-interest as a motive. Price collusion doesn't help you vis-a-vis your competitors either but it's certainly done in self-interest.
If everybody in the economy makes 10% more in nominal terms but output remains the same, nobody is better off in real terms. The industry being deregulated is just a subset of the economy though! If getting rid of a regulation makes participants in an industry which is only 2% of the economy do 10% better in nominal terms while output remains unchanged, those participants are coming out ahead in real terms by capturing a bigger piece of the economic pie.
One need resort to neither altruism nor high minded ideals to explain such an action, self-interest still suffices.