Don't you have this backwards, or do I?
Software development is now going to be treated as R&D, which means that costs have to be amortized. That's not an tax advantage, it's a disadvantage. All the other businesses you list get to expense their labour costs. But we agree, software dev should not be treated differently.
I wonder how this one will pan out.
Let's say you build out a landing page with a way for folks to input their email address which demonstrates interest in your product. You've released it and people can sign up.
Did it launch? You could make case it did and now you're iterating on the product from here on out. You've launched phase 1 of the product which is probing for demand.
Any software development costs related to improving the product by providing new features must be amortized. Only clear bug fixes can have costs that are expensable.
This is made extremely clear in the IRS guidance document.