Well, Steve had a unique ability to see beauty and usability where others see problems and failiure. And not only that, he had the ability to convince people that he was right. He had this from the beginning. XeroX had a great concept going on about a graphical UI and a mouse. The management didn't believe in it because they thought from inside the box, which was textbased operating systems. O boy, how wrong were they. Steve noticed in an instant that this was the future. He had a rare gift about predicting what was right and wrong. Besides that, he was a great micro manager to get remarkable things done.
There was that, but there was also Apple's ability/preference to focus on "doing it right" rather than "keeping it cheap".
Any other company could have come up with aluminum unibody construction, or laptops loaded with connectivity, or taking out the optical drive to make room for bigger batteries. But any other company wouldn't have done it. "Well,
that would be nice, but it would cost way too much." "Well,
that would be nice, but our competitors all have optical drives, we need to have one too." "Well,
that would be nice, but..."
Any other company wouldn't, or couldn't, do some of the braver things that Apple did (such as taking out the floppy drive or optical drive). If HP tried that, people would revolt and buy Dells. But Apple built itself into a nice spot where there was no competition (if you want Mac OS anyway) so that meant (a) you pretty much had to accept whatever decisions they "forced" on you, and (b) they could charge whatever they wanted. So they began to sell their products as premium featured for a premium price.
And it worked. People were initially upset over whatever change Apple introduced but quickly said "You know, they're right, this is better."