I think the main problem is that programs are designed by programmers who think that the users are idiots. Programs designed for programmers have a much leaner interface.
e.g. think about accounting applications:
You had trained data typists in the 60s, who typed the accounting records in a format, that can be directly processed in a batch oriented way.
You had 3270 terminals in the 70s, for trained typists, to enter the accounting data into a form, that was producing the records to be processed in a batch oriented way.
User interfaces become more interactive in the 80s, applications become personal, and there was no batch oriented processing anymore.
Most accounting software requires the use of the mouse now, so its no longer possible to use them for a trained typist, who prefers that her fingers stays on keyboard.
Lets step back:
My own home grown accounting software is written AWK. Its parsing a plain text in a markdown like syntax, and producing all papers I need for tax and accounting with a single "make". Calling ":wmake" is F2 in VI for me. The complete accounting system is 88 lines for invoices, 128 lines for monthly tax, 168 lines for annual tax. Its pure batch oriented, requires no database, and I'm using my preferred interface, the VI editor.