From Wikipedia about ARM:

"The company was founded in November 1990 as Advanced RISC Machines Ltd and structured as a joint venture between Acorn Computers, Apple, and VLSI Technology."

All latest node tech from TSMC was co-financed by Apple who in turn had the first-user right.

But the ARM architecture was originally an Acorn internal project (it was originally the Acorn RISC Machine), with the first Acorn Archimedes systems released in mid-1987. As you noted Apple did invest in the project later, when ARM the company was founded, but they also bailed out in the late '90s when they had their own financial issues.

> The company was founded in November 1990 as Advanced RISC Machines Ltd and structured as a joint venture between Acorn Computers, Apple, and VLSI Technology.

The company was renamed to Advanced RISC Machines to placate Apple - the first ARM processor was the Acorn RISC Machine, which tells you it's true heritage.

That's all correct though the point is that Apple was there as well and its kinda their baby as well.

They are referring to the fact that Acorn, Apple and VLSI were the co-founders of ARM. This is the source of Apple’s very expansive license to ARM