The seats are assigned. People have been standing in line for 15 minutes now. Why on earth would anyone want to stand there, when they could just sit and wait until the line clears?
I understand wanting to get off a plane ASAP, but boarding? You just end up sitting on the plane, waiting for everyone else to get on.
The seats are assigned, the baggage compartments are self-serve.
A long time ago most airlines checked at least one bag free. I used to always do this and as op suggests, not stand in line. It was great not having to take a bag through security and haul it around through airports and connecting flights, and avoid the stress of if the overhead space would run out.
But airlines have done everything in their power to make boarding and the whole flying process miserable in attempt to suck every dollar they can from you for their upgrades and priority boarding.
I do often take advantage of the airlines offer to “we expect a very full flight, overhead space is limited, and will check your bag for free to your final destination”