Having a glue-in does not prevent removal of the trigger. Custom actions that are made for benchrest use generally have trigger brackets, that are attached with vertical Allen head screws, which are reached by removing the trigger guard. Before actions had these brackets, stocks were drilled with holes that lined up with the trigger pins of Remington style triggers, to allow removal and replacement of triggers. The idea that gluing in one of the current crop of benchrest actions, or for that matter a Remington, or one of the clones, does not allow removal of the trigger is simply incorrect. I have one with the bracket, and two with holes in their stocks. I prefer glue in bedding, and it is far and away the most common system used for short range benchrest.
In recent years, the advent of better adhesives, notably JB Weld has made glue joint failures uncommon. One of the reasons that Stiller hard anodizes his aluminum actions is that it gives a stronger glue joint. This is not to say that a good job cannot be done with plain aluminum. Knowledgeable gunsmiths do so all the time.