Other points - you've assumed that from this pair, all steel bikes have lower load limits than aluminium ones.
a. This is a sample of two, and we can't be confident that either represents the "average" of those frame styles.
b. Components. Its not stated in the example, but "N-speed disk brake" could include cable-braked Tiagra, or hydraulic brakes on GRX or any number of other combinations from SRAM or Microshift or other suppliers. So the component choice can make a large difference to the price.
c. As pictured, one bike has front and rear racks, (worth several hundred dollars by themselves) and therefore has hard points to mount them. A bike where the racks are wrapped around stays and brake bolts might be lighter, but are not as robust.
d. Tyre clearances - noone wants to ride for days on a pizza cutter tyre. The wider tyre will be more comfortable, as long as it fits in the frame. Either frame material can have clearances, but that may be relevant in one's choice.
Last point is a little cynical. If a bike maker can sell you another bike, then they make more money. Whether you need a road, CX, gravel, hybrid, and touring road bike, or a dozen different MTBs for various disciplines, that's irrelevant. What matters is if they can convince you to buy another bike.
You can totally ride a commuter on a tour, or commute on your racy road bike, or take that road bike on some singletrack. Will it be "best" ? No, but it'll be fun.
Noone has a bottomless wallet, so we do have to make fiscally-responsible choices, like choosing 105 instead of Duraace. Some people have to choose Tourney because the alternative is no-bike. Rather than agonise over choice, go with the choice you personally find most comfortable.