I certainly agree with this, but both Sun and DEC started out very 'open' and then got more and more closed and vertical and then they died. I have a couple of custom chips in my PDP-8, perhaps a dozen in my PDP-11, and a whole bunch in the VAX. Similar pattern with Sun-2, Sun-3, Sun4, and then Sun 10/20/Ultra... It was the very success that they were experiencing that lead them to believe that they could capture more and more of the 'value chain' until they couldn't any more. I expect this will end badly for Apple but I am open to other ideas about why it won't.
I think one difference is that Sun and DEC were selling to enterprise/business markets whereas Apple sells to the consumer market. I think the former tend to make decisions more based on cost/benefit while the latter tend to be more emotionally driven. If Apple can continue to succeed with that I think they will continue to survive.
What killed Sun and DEC and other RISC manufacturers (also PowerPC) was, that once the PC market grew to a certain size, they couldn't keep up with Intel as Intel could afford a magnitude more R&D costs with their processors and equally had lesser production costs. This shows, that going vertical won't work, if your production numbers drop below a certain threshhold, the economy of scale would work against you.
For Apple, the combined range of iOS devices currently gives them enough scale.
I think Sun could have had a much better chance, if they had pushed SPARC processors into the private market too, like offering a decent SPARC based ATX motherboard for all the PC enthusiasts setting up their Linux machines.
I don’t think either Sun or DEC started out as very open, at least in hardware, and probably in software either. Much of their openness comes at the end of their reigns. At any rate, I don’t think this had very much to do with their downfalls.
In the 1960s and 1970s, every DEC computer came with a full schematic. You could troubleshoot any signal on any board. Most of it was COTS components, and replacements were easily obtained. Also, by 1980 there was a thriving industry of 3rd party add-on boards.
The operating systems were less open, but that had a lot to do with the cost of distributing megabytes of source code. It was possible and recommended to recompile RT-11, at least, from source to optimize for your hardware configuration.
