It\'s easy.. look at the actual gameplay parallels.

Expecially with Quest for Glory, since that\'s the game which most closely resembles Shenmue in terms of gameplay IMO. Everything from improving your fighting skills, playing mini-games, and simple "Simon says" button pressing sequences. And then there\'s also parallels in the enviroment itself... with dynamic NPC conversations, realtime day-night transitions, buying trinkets which have to significance to the actual game, season changes, and time specific events. In fact.. it even goes a step further by altering the gameplay depending on your mix of skills and classes and requiring you to find food and water. And unlike how Shenmue FORCES you to find a place to sleep for the night at 11pm.. you can stay stay awake for as long as you want in QFG at the risk of fatigue and eventual death.
As much as you may not like to admit it.. Shenmue is very much an adventure game which much more closely matches older IF than modern "Squarish" RPG\'s. The game is more polished, more modern, but it\'s roots are firmly based in the past. In fact, Yu Suzuki said in an IGN artical (will find the link upon request) that he drew his inspiration for Shenmue party from old adventure games.. going so far as to list MysteryHouse (Sierra developed, Roberta Williams of King\'s Quest fame to be exact) as one of his favorite old games of that time.
Oh, and BTW: Point and Click interface didn\'t become popular until the advent of the SCI engine which was first used in 1990. Not the middle 80\'s. Unless you\'re talking about LucasArts\'s SCUMM engine.. in which case it was more than 8 bit (unless you\'re talking about the *bleh* NES version of ManicMansion) and did not allow the player to die. Also, I\'m not exclusively compairing a AGI based engine game to Shenmue, I\'m compairing the wide array of adventure games from multiple companies from times ranging from 1978 to 2001.

Opps, almost forgot. The "Point & Click" interface was the SCI engine.. which is 256+ colors. The AGI (which you\'re refering to I take it, was never 4 color. It was always 16 color, but improvements in the engine build allowed for smaller pixels and more detailed scenes. The only 4 Color engines used were with the static graphics Text adventures like "Adventures in Serenia", which weren\'t programed in VGA since the standard of the day was still CGA.