In the early days of SSD adoption there were 'Hybrid HDD' that effectively acted the way you described, using a small SSD as a read/write cache. Ultimately, th

In the early days of SSD adoption there were 'Hybrid HDD' that effectively acted the way you described, using a small SSD as a read/write cache. Ultimately, the price of SSDs dropped to the level were such solutions filled an ever shrinking niche and they fell out of favor.