To the contrary, I am not suggesting outright reverse engineering. I suggested clean room engineering.
Clear room engineering doesn't protect you from patent violations.
This, coupled with a good lawyer and the current precedents in the software industry, should not really cause any problems for people creating software from scratch that has the same functionality as existing software.
Be it an OS's API or an end-user application.
Usually reverse engineering is only allowed for interoperability when there is no other way to obtain the information needed to implement it.
That's what is done with OS APIs for example.
Case in point, Compaq's 1982 clean room engineering of IBM's BIOS to produce compatibles.
That was 8k of code. Somewhat less than big application today.
As to whether it is feasible in a free, open-source environment to create Office and Photoshop clones, I don't think so. It might best be taken on by Amiga, Inc. themselves (which in itself is highly unlikely since it's a dead corporation to begin with).
No corporation can do it or they'll be ground to dust with patent lawsuits.
Then again, every time I look at the progress made with AROS I'm amazed at the dedication and contribution of disparate individuals to create something for fun and not for profit that would take a major investment by a corporation to pull off otherwise.
What AROS is doing is trivial in comparison to even one modern application. The KS ROM is only 512KB and the Workbench applications easily less than a megabyte. Almost everything in the OS is well documented (autodocs & includes) and the applications are very simple.
