I have a similarly frustrating story. After bitcoin peaked in early 2014, I remember its price going down to $177 USA dollars. I remember trying to order a couple from Coinbase, only to be asked a few days later for documents I did not have, and have my transactions declined. Afterwards I checked out other sites to buy bitcoins but price had already gotten back to $400 or so. I though: "I'll wait for price to fall down again then buy." Here I am today, with bitcoin at $2900. Sure, I have been getting some sums slowly from ads, faucets, referral programs, etc, but still...
About Coinbase, I say this:
I feel your frustration, altough we missed out bigtime on these thing, I believe we are still in the early days! We just have to pick the winners, like Steem!
Speaking of Coinbase, I opened an account when ETH was $90. I couldn't get my credit card verified and they had a post on their site saying they were having issues. When all the dust settled I got in ETH at $260. Kinda sucks but I'm still in the money.