Pretty sure those 4x designs haven't changed much in a long time, although admittedly, I don't know squat about the Tavor.
Eugene stoner's armalite rifle: AR10, Ar10t, SASS, Ar15, m16, m16a1, m16a2, m16a3, m16a4, xm177, CAR, m4, m4a1, spr, cqbr, c7, c7a1, c7a2, c8, c8a1, c8a2, c8a3, c8fthb, c8sfw, hk416 Those are the official models (and prolly missed a few inbetween) and not taking into account new finishes on market, improved parts like bcm and rainier cocking handles, barrels, aluminum alloy changes (6061t6 and 7075t6) and now polymer (not an improvement), forged or billet ect. Some improvements are cosmetic, some utilitarian, some are as simple as fire control differences, or hand guard colour. some are major improvements like a forward assist. Barrel materials and procedures, And piston driven models. Ect. Prolly missed some, these are off the top of my head.
Mikhail kalashnikov's automat kalashnikova: ak 47, aks, akm, rpk, ak74, ak101, ak103, ak12, ak107/108, I think it's at ak109 now. And a plethora of models inbetween. Each model built on the next to modernize and improve.
M14: m14, m14e1, m14e2, socom, m14 DMR, m21, m25. And more models in between. Again all built on and improved.
Tavor: Gen 1, Gen 2, Gen 2.5, ctar, x95.
Swiss/sig: 550, 551, 552, 553, 556
Alex robinson's XCR: variants from A to what are we at now K? L?
Overall the designs have remained the same, however small improvements are still improvements, and are continued to be improved upon today with new manufacturing methods and materials. Like I said, this is just scratching the surface.
I haven't gotten into calibers or individual companies claiming Thier rifle is the most tactical because it's black and another company making theirs darker and therefore it's more tacticaller then the previous, ect. People don't even know what that word means anymore because of marketing scams and misrepresentation, same with "milspec".