Many things that become mainstream was at one point a subject of research, but that doesn't mean that the mainstream is "trying to catch up" to research, becaus

Many things that become mainstream was at one point a subject of research, but that doesn't mean that the mainstream is "trying to catch up" to research, because most of what is researched never gets good or appropriate enough to be mainstream. Comparing a language that in its manifest declared that it is "blue-collar" and would strive to only adopt features after they've been tried and tested for years elsewhere and then become familiar with a language that is a tool to try research questions and to judge them by similar criteria is very strange. Scala and Java have very different design philosophies, they are designed for different audiences, and they have different goals. You also seem to be under the impression that more features always mean "better" and that more power always means "better." I am not sure what gave you that impression, but by most reasonable metrics neither of these is the case. Your comparison with democracy is also misused. I think you'd agree that if every person had the right to arrest anyone else or to judge and punish people, our situation would not necessarily be improved. Software, or at least the kind of software that Java is designed for, isn't written by a person but by a group of people, often a very large group of people, and over what could be decades. The goal of various restrictions is to protect the work. Finally, arguments for "expressivity" are just as ridiculous as arguments against it; these are largely matters of personal aesthetic preference.