3E will never need a retroclone, it has the OGL/SRD.
I'm not sure why there are so few attempts to reproduce 2E, the only one I know of is For Gold and Glory. Perhaps there is a derth of 2E product still available, and a majority of 2E contains background material that is valid regardless of edition? (I don't see a lot of praise for the majority of 2E's adventures, even back in the day so I guess people aren't interested in converting any?).
As for my Grand History since 3E and what changed?
WotC went with 4E, implementing a system that was an attempt to expand the play of levels 1 to 10 to be stretched over the likes of 1 to 30. New powers and abilities were granted to give something new at every level, and abilities were broken into "at-will" (any time), "encounter" (once a combat) and "daily" (as on the package). This schema was doled out to all classes. Likewise, most of the D&D lore was rewritten from top to bottom and the focus was primarily on battlemat encounters that were tuned to be epic tactical confrontations. Also, the optional prestige classes of 3E were incorporated into the higher levels, and were no longer optional. Skill challenges were introduced, where the success or failure of certain interactions were passed or failed determined by passing a certain number of skill checks before accumulating a certain number of failures (at the basic level, 3 of one or the other). Rewards were reworked into "treasure packets" that were encouraged to be player wish lists of magic items for their character build.
5E was meant to be a last hurrah, and took the underlying 4E engine and covered it over with trappings of prior editions. "at-wills" were carried over, "encounter" became short rest abilities, "daily" became long rest and were primarily returned to the providence of spellcasters (with some exceptions). Many abilities and powers were retranslated back to their prior edition format and methodology. Almost all classes received some form of spellcasting from level 1, or a subclass that had such an option. Stacking spells was greatly limited by implementing Concentration, which limited most spellcasters to keeping only one spell active at a given time, and the effects of many spells was reduced from the power of prior editions. 4E's idea of subclasses were moved down to the lower levels, ranging from kicking in at 1st - 3rd level (now all are 3rd level with the 2024 rules). The range of bonuses added to characters was trimmed down significantly, in the hopes of making the result of the d20 roll matter more than the added bonuses. Also, Advantage/Disadvantage was implemented, where rolling d20 and taking the highest or lowest replaced a majority of individual numeric modifiers (lot less +1's or -1's, basically). Automatic ability score increases were implemented at fixed class levels (with the option to take Feats instead). Magic items were relegated to "optional", with the characters supposedly having the innate ability to overcome threats built into their classes; magic items were not factored into requirements to have the appropriate power for your level and was "gravy on the top". Also, limits were placed on how many magic items could be accumulated were put into place via the system of attunement.
I think that covers it, or at least all the changes I can recall.