Yeah, but I agree it's not a very good solution.
I've given this problem some though, and I'm wondering if you couldn't actually MAKE a decent grab bar using 2 inch thick wall PVC pipe.
What I'm thinking is to take two 1 foot long piece of 3 inch diameter PVC pipe and cement them into the ends of a 3 X 2 X 3 inch PVC Tee. Do that twice so that you have two identical assemblies.
Now, take those assemblies down to any lumberyard that has a table saw and cut a wide slot in each of those assemblies so that each one can be slipped onto the side of the tub with the 2 inch port on the tee pointing either straight up.
Now make up the grab bar itself using 2 inch diameter thick wall PVC pipe and a pair of 90 degree elbows. The bar would then fit into the 2 inch ports on the side assemblies and would reach across the tub.
You could leave the assemblies at the side of the tub in place, and just put the cross bar in when required.
PVC isn't as strong as steel, but it's plenty sturdy enough to help an unsteady person get in and out of a bathtub.