It has everything to do with those decisions. You make the point about the SSD, which is a good one (though to Apple's credit, the SSD looks like it's actually proprietary, but able to be replaced); you have to pay $100 for 16 more lousy gigabytes of flash memory in an iPhone because of decisions like these.
The point of making that statement wasn't to imply that Apple is wrong because every other manufacturer uses modular components. Obviously that isn't the case. We all know manufacturers have to balance quality, cost, and time when bringing products to market. The point is, it's irresponsible to bring products to market that will not be supportable long-term. Part of supportability is using modular, repairable components that are built to last. As iFixit would say, repair is freedom. Modular components are a large part of repairability. Here's a counter-example: at a LUG a couple years ago I met one of the ZaReason guys, who partially disassembled one of their laptops. I don't remember exactly which components were modular, but it was quite modular for a laptop! Here's another counter-example. Modular designs can happen. It is a choice not to do it.
The fact that you won't be able to find a replacement battery 3 years from now illustrates this point. This is wrong and irresponsible and should not be tolerated. There are significant cost externalities in terms of waste products that the world is paying for due to these decisions. Companies make products that are difficult or impossible to service, and/or utilize planned obsolescence to ensure out-of-warranty replacement, because they know it will lead to more future sales when those components fail. The only difference with Apple is that their products cost more.
If in any problem you find yourself doing an immense amount of work, the answer can be obtained by simple inspection.