Apple computers come with SSDs only on the macbooks, so losing the DVD drive due to bigger hard drives isn't the case here because the hard drives are MUCH MUCH MUCH smaller now. I have tons of customers that face serious issues because they didn't know about this and they don't know much about computers.
Flash might be garbage, but its still super important.
Now lets talk about regular USB.... Apple dropped it without including a free adapter. They could have EASILY added one USB 3.0/3.1 port on the motherboard. There's plenty of space for it, but they would rather have you pay them tons of money for an adapter.