As a non-Mech E, but someone who needed parametric CAD for side-biz[1] projects... the delta between FOSS offerings and paid offerings in this space is immense. I evaluated Fusion 360 a few months back, and even that was a non-starter for my use: I was floored that it doesn't have a feature often called "configurations"[2], vital to my work. Solidworks would be great, but the per-seat starting price was far too high for me right now. I went with Alibre Design on the recommendation of an engineer acquaintance, and that's been my personal parametric CAD sweet spot. I adore OnShape's revisions to classic CAD modeling, but it's still more than I want to pay given[1].

[1] not yet money-making, so still akin to "hobbyist" in needing to keep a constrained budget. I absolutely agree with the parent that the per-seat costs seem high, until you factor the costs of your skilled staff in a real work environment.

[2] Imagine you want to model a cap screw, but have just one master model for all of the diameter/length/{fully-threaded, partially threaded} variations. Updates to the model are then sanely propagated to every variant. You don't have to go very far down this path before manually keeping separate models in sync will drive you nuts. That's the problem that configurations in CAD s/w were created to solve.