Perhaps all those the money Sierra wasted on cartridges for the Atari and Commodore computers soured it on further development for those systems.
You mean stuff like BC and Oil's Well.
They found a niche in the IBM PC market that was not well-served by other companies.
Perhaps so. Sierra had fully committed themselves to the PC platform by the time KQ1 came out while most major devs (Epyx, Microprose, Electronic Arts, etc) were centered around the 8-bit machines. They had AGI ports for the Amiga, ST, and IIgs as well, but those were rush jobs with inferior sound and sloppy programming so it was obvious Sierra didn't really care about them.
In the end, their decision to withdraw from the 8-bit market paid off in a big way as PC clones started proliferating. After 1985, PC game sales were way more profitable than the C64, Amiga, etc.
Actually, the AGI games only work on an 128KB IIe or a IIc, which supports a high resolution bitmap mode with relative color placement freedom.
Which is something the C64 lacked (it has a bitmap mode, but is still effectively a tile-based system)
I was browsing some old threads on Lemon 64 where Sierra games were discussed. They mentioned that the AGI engine is quite a bit more complex than the one used by Maniac and Zak (which were designed around the C64's hardware from the get-go). There's a lot more animation and game logic, in addition to having a text parser (much more complicated than the click and point verbs in LucasArts games). In addition to which AGI was designed for a system with bitmap graphics and software sprites. This was perfectly suited for the Apple and PC hardware, but much less so the C64.
They also said on Lemon 64 that it probably would be impossible to shoehorn the AGI engine into 64k. The Apple II ports as you mentioned require the 128k models, which also don't have a standard 6502 but a 65c02 which was an enhanced version with added instructions. Loading time on the 1541 would also be horrible. The C128 could definitely pull it off as far as memory and faster disk access, but you still have to content with the limitations of the VIC-II.
Technically they had 8-bit ports of KQ1 and KQ5 on the Master System and NES, but those versions are garbage. They do though trade the text parser for a LucasArts-style verb system.
These Apple II ports run much, much better with an accelerator
That it is. They're slow as molasses compared to the PC and have absolutely no sound.
Consider if it takes 8-10 seconds to load a new screen on an IBM PC, PCjr. or Tandy 1000, it probably takes almost double that to load on an Apple II machine
I don't know how fast the Apples are, but the load time isn't that bad on the PC. About 3-4 seconds to load a screen.
I think that for Donald Duck's Playground, the porter had to convert each graphics screen manually. Compare the screenshots on Mobygames, I think Sierra was not particularly pleased with the end result.
I covered that earlier. DDP was written first on the C64 and then remade for the AGI engine.
yes - I believe that was said in the context of King Quest, explaining why they chose to target the (then new) PCjr. An '80s game dev singing the praises of a PC over other platforms wasn't something you heard often
I guess it boiled down to this: Since the PCs allowed much better application software than 8-bit machines, by logic, they should be able to have more advanced games as well. 16-bit CPU power and six times the memory of 8-bits certainly is an advantage.
But even Maniac and Zak, despite being designed around the C64, are still a pain to play on there compared to the PC because of the amount of disk access they need to perform along with not being hard disk installable and needing a special save game floppy.