if Crosby and Ovi played together Crosby would be a consistent 150pt player, and Ovi would be pushing 60 to 70 goals a season
And if Orr had played with Denis Potvin, his stats for a defenceman would have been so utterly unreachable for any other defenceman for all time that his statistical achievements would be spoken of with the same hushed tone we use when we talk about Gretzky's records. Not sure what your point is, here.
Also - With the benefit of modern high-tech equipment (composite sticks, ultra lightweight pads that don't absorb sweat, formfitting and over-enginnered skates, etc...), modern coaching styles (sub-1min shifts and dependence on effective 4th lines that keep players fresher throughout the game, evolution of matching lines, etc...), modern year-long training regimens and diets, modern youth hockey schedules and hyper-competitive junior leagues, most modern players are far better positioned to perform at elite peak levels than anything we saw before... 1990-95(ish) eras when the game started to evolve at a crazy pace.
You can't compare base stats across eras. Mason Raymond would be a borderline hall of famer if you let him play in 1970 with all of the modern equipment and advantages he has in 2018 against the rest of the 1970 league playing with 1970 equipment and 1970 coaching and 1970 "training regimens" (an oxymoron in that era, I'm sure, lol), etc...
The only thing you can compare across eras is pure talent. Orr had more than Crosby or Ovechkin. Everything else is subjective, and so dependant on uncontrolled variables that it's not really worth anything as an argument.