No to MMers getting pre-boarding solely on that basis. They already get Group 1 even if they fly only one UA flight a year (due to automatic Gold status). Get to 3 or 4 MM, then you get pre-boarding solely on that basis. Pre-boarding groups are already too big. Any more and there might be only one passenger in the boarding area after all the pre-boards get on

UA wants to reward passengers who have more recently given them loads of money. UA loves 1 MMers who still fly at 1K and GS levels - and they get pre-board. A 1MM who isn’t flying at that level? Group 1 is still a good deal.