That's a hard one to gauge. People and churches who set dates are usually self-correcting. They usually have a second swing at bat when the first date fails, generally the following year. Usually* because they didn't take into account the difference between the solar and lunar calendars or some such nonsense. William Miller did this with 1843/44, Russell with 1873/74 and Ed Wisenant with 1988/89**. Miller gave up but his successors, the SDAs, were wise enough to stick with the one date and stop setting them. Russell tried again with 1914. Ed faded into oblivion.
You're pretty well right. For a religion that has set quite a few dates, the JWs have been surprisingly successful. They may have learned their lesson about setting specific dates, but they're still trying to whip up the urgency thing.
Interestingly, a couple of decades ago, WT were sniffing around the idea of adding the 120 years that Noah took to build the ark to 1914, presumably to give them a new final date of 2034. If they had decided to run with that one, we might have been seeing a new frenzy beginning to develop, as started in the late 60s with the lead up to 1975. However, the recent WT seems to negate that altogether. They've stopped using Noah and the closing of the ark door as a type.
Will they never set another date? The trend seems to suggest "No". Let's hope they keep following the trend.
* Usually I don't say "usually" this much. 🙄
** I imagine any JWs who called upon any readers of Ed's book, 88 Reasons why Jesus will Return in 1988, would have had some great animated discussions about the clashing prophetic interpretations which both turned out to be wrong (1988 versus the end of our twentieth century). JWs weren't afraid of a discussion back then.