Mackinnon is on pace for 127 this year after 140 last year and a pace of 126 the year before. Kucherov had 144 last year and this is his third season pacing north of 120 points.
My hope for Bedard is that he's able to surpass 100 points most seasons, with a peak of maybe 110-120, so long as he gets a legit top line center to play with. Similar to Patrick Kane if everything works out.
I think expecting anything more is completely unrealistic. Yeah he was a generational junior player, but it just hasn't translated to the big league (as many suspected it wouldn't).
As far as 19 year old seasons go, he's really not doing anything remotely unprecedented. It's fair to say he has fallen significantly short of the expectations of people (like yourself)) who once thought he'd be better than McDavid.