it seems like all this tech would make random lookups abhorrently expensive
SSDs are virtualized (like virtual memory), so there is a mapping table from virtual to physical addresses. This is needed for wear-leveling, so you might as well also use it for thin provisioning (aka trim), dedupe, etc. In the worst case, one read command may require reading several pages of metadata from flash to find the data. Because flash is fundamentally so fast, an SSD can tolerate a lot of overhead and still be faster than a hard disk.
SSDs are virtualized (like virtual memory), so there is a mapping table from virtual to physical addresses. This is needed for wear-leveling, so you might as well also use it for thin provisioning (aka trim), dedupe, etc. In the worst case, one read command may require reading several pages of metadata from flash to find the data. Because flash is fundamentally so fast, an SSD can tolerate a lot of overhead and still be faster than a hard disk.