Agreed, however there is also a reason why the best ones also pack multiple GC algorithms, like in Java and .NET, because one approach doesn't fit all workloads.
Minecraft for somewhat silly reasons was largely stuck using Java8 for ~a decade longer than it should have which meant that it was using some fairly outdated GC algorithms.
Java has a quite strict max heap setting, it's very uncommon to let it allocate up to 25% of the system memory (the default). It won't grow past that point, though.
Baring bugs/native leaks - Java has a very predictable memory allocation.
This only really ends up being a problem on windows. On systems with proper virtual memory setups, the cost of unused memory is very low (since the the OS can just page it out)
Unfortunately, the JVM and collectors like the JVM's plays really bad with virtual memory. (Actually, G1 might play better. Everything else does not).
The issue is that through the standard course of a JVM application running, every allocated page will ultimately be touched. The JVM fills up new gen, runs a minor collection, moves old objects to old gen, and continues until old gen gets filled. When old gen is filled, a major collection is triggered and all the live objects get moved around in memory.
This natural action of the JVM means you'll see a sawtooth of used memory in a properly running JVM where the peak of the sawtooth occasionally hits the memory maximum, which in turn causes the used memory to plummet.
For video games it is pretty bad, because reading back a page from disk containing "freed" (from the application perspective, but not returned to the OS) junk you don't care about is significantly slower than the OS just handing you a fresh one. A 10-20ms delay is a noticeable stutter and even on an SSD that's only a handful of round-trips.