Why doesnt Mach3 support usb instead of parallel port? 
I would like to use Mach3 with my Shapeoko but find having to use such old technology pointless.
It is 2016 not 1996.  I have not seen a parallel port on a laptop in 15 years and over 10 years since I have seen one on a desktop PC.
Everything I have read points to Mach3 as the best software for hobby CNC, but I find it hard to believe it is so far behind the times.  I will not be able to use it if it requires obsolete technology. 

You could do as I do and use an Ethernet Smooth Stepper (also available in USB version) http://www.warp9td.com/

Alternately, there are about a dozen other types of external motion controllers to choose from - some (generally Chinese) have the limitation of only working with Mach3 whilst others will also work with Mach3 and Mach4 (using different plugin software).

Tweakie.

The way I see it is that the parallel port gives good functionality for inputs/outputs etc, which is exactly what CNC is all about.
If your PC doesn't have a PP simply install a PCI - PP card (penty on ebay) to the mother board and your good to go.

Mach3 does not work with the stepper controller on a Shapeoko , you would need to change to one what does. and there is usb and ethernet options like a pokeys, ESS and quite a few other's. I run a ESS and next week a pokeys 57cnc

Why doesnt Mach3 support usb instead of parallel port?  

To use a USB device you first need a device with enough independently addressable inputs and outputs, this is what Art Fennerty's parallel port driver achieves through a parallel port, then the manufacturer of that device will have to develop and support (at least until it's fairly mature) a plugin for Mach3.

Even if you had a USB device with a parallel port on the end it's driver would have to support individual pin addressing and you'd still need a plugin to allow Mach3 to run a piece of non-standard hardware.

We currently have all the USB devices for which manufacturers have been bothered to develop plugins, so you see, it's hardware manufacturers that are behind the time and not Mach3.

There are still suitable cards available but you do need to ensure that the data voltage for your BOB and card are compatible (you could do this with your own buffering hardware if you did a little research and built a board;-) ), I haven't contacted StarTech to check the logic voltage for this - http://www.startech.com/uk/Cards-Adapters/Parallel/1-Port-PCI-Express-Base-Parallel-ExpressCard~EC1PECPS - but it is IEE1284 and specifically NOT USB so if it's compatible with your BOB it may provide a way forward.

Failing that there are still a lot of cheap, ex-corporate desktop PCs which are up to the job and likely to give many more years of service.
Until last year I was using a pair of HP Compaq d530 PCs which had run for over 5 years, after the live machine became problematic I swapped out for the spare and investigated alternatives, now I'm using a pair of HP Compaq dc7100s (£40 each - delivered) for CNC and am working on options for their replacement/retirement.

Tweakie has offered a solution which allows you to avoid "Obsolete Technology" but there are thousands of CNC machines out there happily running on "Obsolete Technology" so if it's Function and not Fashion you're interested in then it's still a perfectly viable setup

Regards,
Nick

The older the PC the better for Mach3

I'm running fully updated Windows 7 without problems, provided your PC supports the control output device of your choice there's no need to pick older hardware than necessary. I don't have the PC on the network whilst running Mach3, just for data transfer and maintenance.
 
 - Nick

I have it on 8.1 with a ESS no issues.