It's also worth adding into the mix that not all dyno's are the same, some are a pure inertia dyno, some have retarders. Mapping on the road can have it's flaws too, what if you tune it on a nice flat straight and then the driver goes up a hill causing the ECU to hit load sites that weren't seen during tuning?
As a dyno owner/operator/tuner I have seen the pro's and con's of dyno Vs Road tunes. As someone has said you can have everything set up sweet as a nut on the dyno and then hit the road and the boost can over shoot quite easily if not set right, that's why a road test is always advised after a dyno session. This is a bit difficult for track cars but that's why a lot of tuners will offer track side support to review the data from on-board loggers (where available). All of the hard work will have already been done, timing will be optimised, fuelling will be correct, it's just the real world behaviour of the turbo that can be an unknown, which is probably why some operators will hold it back slightly, making the car feel less responsive.
When road tuning unless you have a huge wealth of experience and/or are dealing with a knock limited engine there is no way to know if you've truly got the timing right, this is where dyno's with retarders come into their own (and inertia dyno's fail), the ability to hold the engine at a set RPM point whilst the operator optimises the timing is a phenomenal tool.
Back on topic, Uprev is just a software like ECUTEK, the owners are protecting their investment and recouping their costs by having a licence, this way they can continue to pay their staff to improve their products. The ability to remap the OEM ECU can be done using other tools but to edit the file you're best to know hexadecimal code to understand the data before making changes, I for one am not a software engineer which is why I pay for products like Uprev to allow me to do what I know what to do.