From where I stand on this yes the hardware is rather similar, but the programming is different and the tests to be approved are also different.
There is also the support issue, this all costs.
The test for compliance are rather steep and expensive here and the specifications on the frequencies are also different.
I will admit that most of the VHF frequencies are common world wide but the uses vary. There is also the issue of frequency modulation and tolarences. I could power up an old spark HF set and be heard on it, but it would radiate over the whole band - hence why they are not used except in dire times.
As for the hardware well look at it like a PC, yes you can buy the bits and build one yourself and write the code - in that case my I recomend the RSGB foundation course http://www.rsgb.org.uk
You could buy the same box in varous places in the world but the software options are different.
As for service support sorry you get what you pay for.
If you look at all the players models you will notice a difference between UK/ EU and other markets.
I'm not an Icom employee before you ask, once did some work with them for PMR when I working in that industry.