This is probably more work than you want to do, but I would rewrite these with strong cliffhangers. Easier said than done I know (I write typical romance series, so I can't really use traditional strong cliffhangers). But you're not doing yourself any favors wrapping things up. Readers are not nearly as loyal as many authors claim. Way more readers will keep reading because they MUST KNOW WHAT HAPPENS than because they thought your book was pretty good.
With a strong cliffhanger, a price jump between book one and two is less of an issue. Of course, you can still publish at .99, but I wouldn't do that unless it's common in your genre. The .99 price point is just not used as much these days.
I understand what you are saying regards cliffhangers and obviously that works for many others, so every credit to those that use them to good effect.
However, I have a different take on a trilogy as opposed to an ongoing series which may not end or have ended if not concluded as yet. This is assuming the series is not such as Harry Bosch, or Jack Reacher, all crafted as standalones.
I have a different way of crafting my trilogies to having serious cliffhangers. In effect, that is to have a definitive ending at the end of the third book for the overall trilogy plot. Each individual book is plotted to the three act structure, all with endings to the main plots for those individual books, and with each book in itself an act in the overall plot. However, unlike Jack Reacher or Harry Bosch, the trilogy has to be read in order for the reader to experience a regimented story curve and character development over the trilogy.
An exception to a series similar to my trilogies in crafting with more than three books would be, say the Harry Potter series, which each book has definite endings but also an overall plot.
That is not to say there aren't questions left that need to be answered at the end of book 1 and 2, but the are not the thrust of each individual plot and they could be discounted to provide an overall satisfactory read. If a reader chooses to ditch the trilogy after the 1st or even the 2nd book because I haven't hit their sweet spot, then so be it.
I can understand that as self-published authors, we are not constrained by trad-publishing norms, which is to publish as a standalone and only if it is a success, to consider a second or subsequent books. Some doorstoppers have even worked by splitting them into separate books if the doorstopper was successful.
In my experience as an author, it hasn't worked well for me by publishing standalones as none of them have been bestsellers to warrant the effort of writing sequels, even though reviews have been on the whole satisfactory. Even with having other standalones in my catalogue, it could be that readers haven't been turned on by the other books to want to read them even if they enjoyed what they had read. I am working on an assumption that if they have enjoyed the 1st book of my trilogy, they might be more inclined to read the 2nd, and 3rd book if they are sufficiently invested in the characters.
I understand that your suggested method of cliffhangers can be successful, and many are, but equally, many authors publish with the intention of publishing more and when they don't turn a profit or meet expectation, some authors ditch them, leaving unsatisfied readers who have invested time in reading what was on offer to date. Hence, this motivates me to write the complete trilogy before publishing and to publish it complete on the same day.
I have listened to what has been said in posts about staggard publication, but I am not convinced to have the bottle to do that. All I can say regards staggard publishing, is that when I published my last trilogy all on the same day, it was exhilarating to see sales of or KU downloads of the 1st book from the off, then quickly the following days to get sales and KU reads of the 2nd and 3rd book, with even some buying all three on the same day. This lasted for a good 12 months, though it has now died a death. However, it cost me $30 to publish all three, and so the income was welcome while it lasted and I now have the opportunity to go wide and make the 1st book free if I so wish to resurrect income..
As this is to be my last effort at self-publishing, the last thing I want is to have an unfinished series.
Really appreciate your input. Thank you. I agree that with hindsight that the 99c price point is maybe not a good idea..