Both Gain Capital and OANDA were opened in the 90’s, so you are talking about 20 years, so the retail end of Spot Currency Trading in the US is a pretty mature business. As far as regulation is concerned, here is the big change
http://www.cftc.gov/PressRoom/PressReleases/pr5883-10
This was 2010 when it was enacted, before that, well it was the wild west, 100:1, 500:1, 1000:1 leverage, programmed slippage and delayed fills and quotes, horrible re-quotes, brokers/market makers not segregating clients funds, etc. This had nothing to do with how long or “new” to the US Retail Spot Currency Trading had been around, and everything to do with the trader getting abused, and generally ripped off.
Six years ago, you couldn’t swing a dead cat without hitting a “FOREX” market maker/broker. Now, not so much. Back then anyone could be an IB, me, you, anyone. Now if you want to be an IB, brokers require one to have at least a Series 34, which by the way only costs $80 with no sponsorship needed. Again this was in response to the horrible abuses taking place at this time.
A side note, if you like you can follow this link, and it will explain why FXCM has been banned from the NFA. Learn Why The NFA Barred FXCM And What It Means For Forex Traders
As far as "more Brokers Getting Involved, well they have already been and gone, and I present as exhibit A and B the following.
A. US Forex Dealers See Continued Decline, Opening Up Fresh Lows | Finance Magnates
B. US Regulators Victorious: Forex Dealers Data Hits All Time Lows | Finance Magnates
The incentive for most people to try Spot Currency trading was, back in the day when there was almost no regulation, the 100:1 leverage, the thinking being, "I can make 100k a year with just 10k invested, 60 days later the 10k is gone and the next sheep comes in to be sheared. This industry was selling a unicorn fantasy, and it was a never ending churn of uninformed, hopefuls, who never had a chance. Once that incentive was taken away. Well the whole thing collapsed.
Yes, the regulations caused some of the decline, but bottom line, at this time, there are not enough people that can trade to keep the retail business open to hundreds of Broker/Dealers.
So I hope you find a trustworthy broker.
The Ever Institutional VIPER