Possible Reasons to not have wireless in 2050 (just my stab at the question)
In-Game - Advancement of technology has not been consistently smooth and progressive
Firstly, the Crash 0f '29, plus Vitas plagues etc has meant that scientific progress has not always been smooth. Technology has not progressed at the rate that we, today in our far more stable world, would expect. That said, the move from large, slow desktop computers to wireless tablets has taken about the same amount of time in the real world. How soon before the next generation wonders how banks etc ever worked before the internet?
In-Game - 2050 is less then 20 years after the creation of the Matrix.
In 2050, Matrix tech is still fairly new, at least compared to 2070. The ability to access a fully submersive reality via your commlink is far in advance of the tech of 2050. In 2050, Black Ice (while born from the Crash Virus) are still fairly cutting edge and no decker has Black Hammer type programs. Its just too soon after the crash for these advancements to be made. Really, even in real life it would be pretty extreme to go from creating a Matrix system to wireless VR reality in less then 20 years.
In-Game - Corps slow technology progress.
Ok, this does have some holes, but oligarchies are just not as competitve (economics 101). Megacorps will slow down progress, or at least not compete in R&D as much as they do today if they already own and dominant the market. Look at the desk-top manufactoring example in Arsenal. Megacorps may compete... but only in little steps. When Renraku did turn up the speed, the other corps weren't happy...
In-Game - If it ain't broke, don't fix it.
Ok, so the creation of a wireless matrix was actually a pretty big piece of infrasturcture work. Its up there and beyond bringing in mobile phones etc. And while the old Matrix worked, there was no real money to be made in creating a wireless matrix... yet. So the corps didn't push something the market wasn't ready for yet. It took the 2nd Crash to give the market leaders an opportunity to release their product....
In - Game - It did exist, but wasn't mass produced and released to the market.
Ok, look how quickly the corps did roll out the wireless matrix. Having been involved with some cutting edge r&d, I have some idea of how long it takes a concept to become mass produced consumables. Theory, wireless matrix tech was ready to go and was just waiting for the right market conditions.
Now some out of game reasons:
Out-of-game - Style/Atmosphere
2050 tech was based on cyberpunk fiction from the 80s. 2070 tech is based on similar ideas from the current decade. They both create different feels/styles. I suspect a lot of us who are looking very much forward to the 2050 book loved 'deckers', loved the feel of the old chrome and wires and keyboards etc. To introduce wireless stuff would sinificantly change the feel of the book and thus may negatively impact buyer reciption.
Out-of-game - impact to timeline/universe
The Wirelss Matrix is tied to a major event of the unverse. To introduce wireless into 2050 may make some sense (in how we see tech progressing in the real world), but would upset the apple cart somewhat fierce in the setting.
Out-of-game - progress of technology in the universe
One of the best things about a long-running setting like shadowrun is how tech has progress inside the universe. Technology progress is something you can actually follow in the setting. But it you add wireless matrix and other 2070 tech to 2050... then either tech doesn't progress at all in the 20 years of the game... or 2070 tech needs to be updated to .. what.? Something we cant even imagine?
Anyway, those are my thoughts on the subject. Enjoy!
