Ok, so sometimes - you must have legacy support. Maybe your work depends on it. But you know where legacy support is not "a must"? Ports. Why? Because you can change cables, get adapters, etc. No, it's not a big deal, so man up or woman up - and accept that this is so that we can have better things.
You want things "to just work"? Say no to legacy support. You want companies to focus on innovation? Say no to legacy support. No great breakthrough was achieved in the comfort zone. Short-term convenience or long-term advancement?
This just daft rhetoric as the absolute underlying principle and foundation for the USB specifications 3.1 Gen1/2 is legacy support for USB-2/3
Whilst I have no doubt that USB-C ports are the way forward and they project >90% of laptops and >50% of smartphones will have 1 or more USB-C ports by 2020, however there is reported 10,000's of existing devices and accessories vs relatively few currently for USB-C. There may well be projected 2 Billion devices with USB-C in the next 3 or 4 years vs the many billion still in circulation etc and still being sold with USB-A
The USB org's recognise this and so should you
USB-C is only a port that now facilitates a greater range of uses in addition to latest USB specs which is equally available in the USB-A ports. However the USB-C is more compact and has greater scope to expand.
USB-C has already caused much confusion simply by poor labelling, identification and misunderstanding that it is just a port and the specs of I/O etc for that port are now much more complex and dependent on the OEM. Let alone what less scrupulous manufactures have been doing with cables and adapters etc
Whilst many of us can afford $2k laptops, many more struggle to buy their dream machine. Given that Apple have increased the entry point for the MBP by a significant % (ie the $100 delta ignores this) there are large groups of users that simple cannot afford the additional burden now placed on them for dongles, cables adapters let alone swap out existing devices
Add to this the users who could not afford the Apple Tax on increased SSD size and could previously opt for a smaller drive with a supplementary SD card to save a few more $ and don't even think about $1k EDGU addons
I hypothesise that the MBP is probably is at or nearing the limit of USB-C power and those that wished for a bigger battery etc were stiffed by over enthusiasm for USB-C, unless you want the ugly solution of dual port charging.
I also note the essence of having a laptop is mobility (ie pick up and go) and not having little bits and pieces dangling around, some legacy ports gave a far neater and smarter solution to mobility. It's not all about buying some cheap and probably non compliant adapter to add to the clutter of bits you have to cart around else we would still use mouse instead of a trackpad
Larger more powerful laptops for charging will probably not be able to use USB-C charging and cable length limitations will also be problematic for some
Yes USB-C ports are useful and moving forward yet there are many user cases that can give good reason to justify legacy ports and it will take sometime for universal acceptance and we should not so casually dismiss others needs in advancement disguise of technology IMO