[HarrisonFisk]

There is nothing that prevents these from being implemented for PostgreSQL. In fact, they have already done a lot of optimizations that close the gap, such as covering indexes. Before covering indexes, InnoDB was even further ahead of them.

Of the ones mentioned, I would guess compression is the most complex. For InnoDB this took many years to get the point of it being usable and efficient. Many naive implementations can cause huge overheads for CPU which makes it unusable.