Good business practice means looking for market niches that are unserved or underserved and filling them. If there is demand enough to support a simpler machine with a large harp, some manufacturer will eventually fill it. Then the rest will follow when they see the profits to be made.
Unfortunately, there isn't enough competition in sewing machines (unlike the car market, for example) to see this happen quickly. It's why I bought a Bailey's long arm instead of a TOL sewing machine. I could get something that did just what I wanted and nothing more for less $$. Worked for me.