Well, if that's their level of commitment...give the raise only to those who bargained collectively. The others are, indeed, on their own. Make opting-in an annual thing, like health care changes etc.
Makes for a volatile working environment and would prolong contract negotiations. Work to rule would be disastrously inequitable. As I mentioned, a licensed teacher can get a job in a private school and not be bothered with unions.
College professors do indeed consider themselves professionals--they're not licensed professionals. For the most part, only state schools have unions and not even all of those. Most schools do not have professors' unions. Tenure is as strong at private colleges (not high schools) as at public ones.
Our profs are unionized. They can also achieve tenure. There's no such thing as tenure in my profession; however, as one accrues seniority, ones position is more secure.
The popularity contest part is an argument for unions--but then, it applies to a great many workers. There's a stronger-than-usual argument for teachers as teaching styles can vary so widely, but it's hardly a given.
I wouldn't say it's a given, but my gut tells me that there are, sadly, many parents who drop their kids at school, so they can go to work. It's up to the profession to remind everybody that we're not the nanny. In general, I would say North Americans have a consumeristic view of schools.
To give you an example, a previous government in Ontario unleashed a huge package of reforms on Ontario education, including a new funding formula (which never worked), common curriculum, standardized testing, and accountability initiatives. Part of this package would have given parents the right to evaluate teachers. Naturally, my union fought it. School boards, the management of teachers, essentially circumvented the plan as well -- they weren't crazy about it either. We came perilously close to having what amounts to a popularity contest.
The problem with the customer service view of education is simply this: my job isn't to please parents. Nothing makes me happier than to have productive communications with families and to find them satisfied with what my colleagues and I provide. It's a public service, like a city bus, not a customer service, like a limo. The rider doesn't dictate the ride.