Because the end of hl2 and the ‘episodes’ hurt us. I didn’t get over it until code Geass hurt me more with the I am zero scene, and then I suffered for 8 months or so only to be subjected to that damned reboot fake out. I haven’t played hl alyx in fear of it not bringing any closure and judging by how I haven’t seen any headlines suggesting that and people still wanting hl3, it’s probably safe to assume it doesn’t. I have largely moved on but if they ever do make hl3 and I’m not on my death bed I will probably marathon the series like I did with dark souls, including the duplicate ds1 and ds2, my job be damned.