Design is not the same as tape-out. ARM designs the logical structure of its chips (the VHDL or Verilog). They then license that design to customers (such as Apple, Samsung), who customise it.

The tape-out is completely separate from that. You need to do the physical layout and produce a set of lithographic masks that are incredibly expensive. Back in 2000, a set of masks for the most advanced technology at the time was already in the millions of dollars. Things have gotten ridiculously more complex since then.