Considering how many people work in O&G, it's not hard at all to believe that many people save $1500+per month with RRSP matches from the company. My company matches up to 18% (9% each), and I have a friend whose company matches up to 20% (10% each). Most people I know get at least 10% (5 each), with many getting more than that. It comes off your paycheck before you get paid, so you don't even notice it, and you never miss a contribution.
Say you make $100K, for a lot of people that's $1500+ right there getting put away without any additional contributions whatsoever. For those getting less, it doesn't take much every month to top that up. Add to that anything else you contribute, maybe at bonus time or whatever, and it's really easy to see how people get $1500+. Outside of O&G (or any other RRSP matching environment) I do think it would be difficult to save that much.
Some people are crazy savers too, and they live paycheck-to-paycheck just so they can put a huge % of their income into savings.
IMO the 2 biggest problems with saving are people who chose to be house-poor, and people who have to use daycare. Daycare can be INSANELY expensive if you don't want a live in nanny or whatever. In my building, for example, it's $1700 per child per month. If you had 2 kids that's $3400/mo + probably another $2500 for a mortgage