As we all know from the latter years of the strip, Lynn and the Pattersons really don't have all that high an opinion of professional musicians. You can't trudge through all of the older Pattersons' commentary about how Becky was ruining her life trying to make a career out of what should be a fun hobby that she's supposed to share with friends while doing something productive and socially beneficial with her life instead of being a bird in a cage destined to die in a gutter without coming to the realization that Lynn is, despite being told not to, sending Alan a message. The reason that I reminded you of this is that back in the early years, she used to be somewhat more direct about nagging him about giving up on something useful so he could torment himself trying to chase the impossible. This means that the preferred endgame to Mike's trumpet lessons was to get Phil to angrily decide that teaching children was a non-starter but becoming a licensed contractor who Elly could actually boast about being related to was a great and glorious thing. It seems to have been Elly's Plan B after her plan to ensnare him into making a serf of himself by marrying Connie failed.