As you can see, once you get to the $750m in sales, revenue growth gets harder to come by. Even if we assume that LULU grows revenues by 35%,35%,30%,30% and 25%, over the next 5 years respectively, it's tough to justify today's valuation.
Let's just suppose revenues scale massively as noted above- $627m, $846m, 1.142m, $1.485m, $1.931m, $2.413m
At year five, growth is beginning to slow and valuations coming down to earth - 2x sales would be generous. That leaves us with a 2x $2.4b = $4.8b market cap. Let's not forget dilution from secondarys, stock/option issuance, etc.
Bottom line, 5 years from now LULU will likely not be trading at a market cap of more than $5b - where it is today. Most likely will be trading below $1B cap