To add more evidence to your point: SJ loved wall gardens and consistently fought against extensibility. The Apple II only got extension slots because the other Steve insisted. All of the compact Macs have very limited to no extensibility.
It's so ironic that Apple was pushing the (open) Web apps in the early days of the iPhone (out of necessity of course).
Jobs loved excellent user experiences, and, rightly or wrongly, saw walled gardens as an important part of providing them. Sometimes.
The counterexample is the iPod, with its advertising slogan "Rip. Mix. Burn.". The first iPod used Firewire and was Mac-only, every edition since then used entirely industry-standard technology, USB and MP3. The value proposition was, as the slogan illustrates, easily taking your CDs and putting the music on the iPod. That too was in pursuit of an excellent user experience.
Later, Jobs fought the entire music industry for the right to buy digital music, not just rent it. And won.
It's so ironic that Apple was pushing the (open) Web apps in the early days of the iPhone (out of necessity of course).