Have floating islands become more rare in recent versions? I still find them but not as frequently as in the past. It seems floating islands became much less common with the release of 1.15. It could just be sample bias, so I'm curious what other players are finding.
The Meaning of Life, the Universe, and Everything.
Not behind you
Unless you're using special world generation, there shouldn't be any floating islands. While there can still be some floating blocks, they shouldn't be far enough from the ground, or large enough to be considered floating islands.
There haven't been any significant changes to terrain generation since 1.7; in fact, 1.7 and 1.16 produce nearly identical worlds down to the majority of terrain and biomes (only oceans have really changed, and only in the addition of new variants which simply replaced parts of the old biomes, same for parts of jungles becoming bamboo forests, etc); a seed with floating islands in 1.7 should produce the same terrain in 1.16 (or very nearly so, as 1.13 did make major changes to how world generation works internally, but I never saw any reports of chunk walls occurring when people upgraded, as would occur if they changed terrain/biome generation, except in oceans. Otherwise, any other changes only affected "decorations", such as trees and villages).
Also, floating islands do generate in default worlds, mostly in mountainous biomes, especially Savanna Plateau M (or shattered savanna or whatever it is called now):
Floating islands are structures that float in mid-air. Floating islands are normally just small chunks of floating dirt and stone found near cliffs, but on rare occasions they can be large structures that even have springs and trees on them. Floating islands are most frequently found in mountains biomes, along with the "hills", "mountains", and "modified" variants of most biomes, especially shattered savannas.