Once the mobile phone had more and more-up-to-date material available there were fewer reasons to buy a magazine.
Nowadays a magazine is something I purchase as a luxury when I specifically want to be offline and without distractions (but even there my Kindle usually does the job just as well).
I must say I miss the quality and depth of writing that one got in Byte and PCW of yesteryear - even though I recognise that the online stuff often exceeds it in both breadth and quality.