Hi Leehu,
In a nutshell, yes, getting full access to JUCE 4 and the Projucer cost $2,997 per seat, where it used to cost £699 to a company.
There are many reasons for that price increase. First, the team, and we hope the support that you receive, have both increased. We have great ambitions to make everyone's workflow the best possible, and it's only possible if we build a great team that will investigate every changes in OS and plug-ins format, so that you dont have to. Second, it wouldn't be fair to compare JUCE 3 and JUCE 4, as a product, given that JUCE 4 comes also with the Projucer, a vastly improved Android support and over 300 bug fixes and new features. Third, we will prioritise support for paid customers on the forum, investing more time in solving hard issues.
Finally, JUCE 4 has a new subscription model, so you can choose to pay per month, starting at $49. And until you release a commercial product on the market, you don't have to pay anything and can use the source code as you please (within the limits of the GPL).
We do apologise to those of you who cannot afford to pay for a full license, and hope that if you are starting a business, the monthly payment license will appear reasonable and worthy of the investment!