scoot - First off, were we IA, I have no doubt that coming in at or just before tech would be regular practice. That's when the regular IA crew comes on - tech. The produceres can't afford them sooner. The only other viable option for SMs is to be hired out independently, unattached to a union and its protections (like our LDs, SDs etc), and flat fee'd for the run of a show. And again, here, I don't see them bringing in an SM sooner than absolutely necessary due to cost. WE know the difference when a good SM is part of the rehearsal process, but so many producers don't.
In terms of the value of being members of IA, I also completely disagree. I have been in and out of IA houses on tour and work with a semi-regular crew for a monthly event here in LA - and the experience is so varied from house to house it's scary. When I walk into an IA house, I am stuck w who is assigned - that person isn't there for the artistry, the show or to think (let alone critical and independent thinking). That person is there for the paycheck. Period. Sometimes that person is good and knows what they're doing, and sometimes they aren't. But there isn't a damn thing I can do about it.
Mind you, I have the occasional lovely and wonderful crew, and have a couple of IA folks I treasure (including two on my regular crew here), but I have also had troubles. I have had to deal w IA crew members on drugs, not taking vital initiative in potentially dangerous situations, not knowing how to set and clear props, walking under moving flies etc. In one case, the SR Carp didn't want to be there and managed (on the 5th nite) to get himself hit in the head w an incoming pipe. Were we able to trade him before this for someone who knew what he was doing? No. Did IA have an arrangement to cover while he sat with an ice pack on his head or when he left to go home? No. I did his shifts. Because it had to be done, and there was no one else to do it, and my union allows me to do what I have to so the show can go on. I've seen bored IA crew members pull pranks and that disrupted performers on stage let alone SMs backstage. DId I have recourse? No. On one tour, the crews hated the PSM; he was calling from the deck, and in three of the houses the carps managed to run over his feet with every wagon shift. (FWIW when I called the show, no toes were endangered.) I had a local sound crew, someone I otherwise respect, get pissed because of one (granted stupid) woman's attitude and simply "forget" to set up her stuff correctly so her performance was sabotaged. We don't/won't do that.
Not counting that using IA costs more ot the producers.
As an SM, I consider myself part of the artistic team, being what someone once said is called "the fifth actor." What I/we do takes skill, training, and artistry. I need to know how to breathe with my actors to call cues, to direct (both keeping the show in line and training the u/s), how to tell my various teams what problems to fix and be able to talk someone thru them on the fly if we are mid-show when a personnel or costume or light or set emergency comes up (or at least know how to talk someone thru options). The show must go on. That isn't possible w IA.
Yes there are things to be fixed. That's why I got active in AEA - to take responsiblity for and control over my career. But I also know from experience that my union supports and protects me, and I can instigate change as needed by speaking up. Again, this isn't so in IA. There is too much more to change in IA than in AEA to have it be a good fit.