Lots of people kick themselves daily for not buying Bitcoin at $100 or less back in 2010 or even earlier, but the truth of the matter is that it was quite hard to buy Bitcoin in the first few years. Most people were steered towards online exchanges, but those proved to be hackable or subject to confiscation. See Mt. Gox as the largest example. Then the currency controls in the USA tightened with "know your customer" requirements and most people found out that they could only buy Bitcoin with a high $100+ minimum to a foreign bank with an expensive $35 wire transfer fee and lots of paperwork to sign physically at the bank. Online exchanges that link to an US bank are still rare (https://gemini.com/), while some use Visa credit cards to do the transfer to Bitcoin on an online exchange.

Most desktop wallets are still in their Windows 3.1/95 stage (think Bitcoin Core/QT or Monero Wallet), although multi-coin "lightwallets" such as Exodus (https://www.exodus.io/) show promise. But most new users of crypto currencies don't have the time (seven to twenty days, even on 20-50 GB cable modem) or the hard drive space to download six or more blockchains for their desktop wallets. You have the "cart and horse" paradox of choosing which alt-coin to invest in based upon which online exchange you can access with your USD, and which alt-coins you can transfer to a single wallet or multi-wallet on your desktop. Developers need to provide better programming in the form of wallets for their alt-coin, rather than depend upon the exchanges to offer their Initial Coin Offering (ICO) at startup time.

There are other issues, such as unreliable smartphone wallets, lack of smartphone wallets, and negative government official attitudes towards crypto-currencies in general, and for good reason. Crypto-currencies are doing to online banking what the Internet has done to newspapers and telephones. What was once the privilege of the ultra-wealthy to travel between countries with diplomatic-sacrosanct pouches is now possible for the average person with their currency.