Why?

Should be relatively simple to extend the "soffit" so that it lines up with the refrigerator. It involves some minor framing, drywall, texture and paint.

Wrong. Soffits/furdowns/bulkheads house plumbing, electrical and hvac (as in this case).

zmith - sometimes, but not always.

I guess you don't see the air register in the OP's photo above.

zmith - I did see it, but I am just stating that it isn't always the case. If it were me and I was remodeling my kitchen, I would relocate it. Nothing like putting in a whole new kitchen with a soffit.

I'm putting in a new kitchen and adding a soffit. The horror.

Make the soffit bigger?

So what can solve this issue is to move the soffit out to line up as Zmith stated however I had this challenge with a kitchen I had my contractor also put molding on the soffit and I painted the cabinets and the soffit and molding all one color and it made the kitchen cabinets look more custom. I tried uploading the picture but I wasn't able to do it. Sorry once I figure out why it won't upload I will do so.

Maybe post a to scale floor plan and you will need to know what is in the soffitt if at all possible get rid of it It might be that we come up with a different layout altogether . A little picture of one space is really not helpful I actually do not like fridges and wall ovens sxs if at all possible