Hate to rain on this (TBH I don't):
Shopify has raised (per Crunchbase) about $122M in funding.
At the current rate, they will see $374M in GMV on their best day of the year.
Shopify has between 1K and 5K employees (again Crunchbase). Let's make the most conservative analysis and assume 1K. If they are paid $20 per hour (low estimate I think), that is $41M in employment costs per year. With taxes, office rent, healthcare, etc, lets just lowball again and call it $50M/yr for all the people costs. Again I think this is a huge underestimate if the crunchbase number is accurate.
Lets assume no marketing, hosting or other costs of any kind.
The internet claims 100k stores use shopify. Lets assume they all pay for the standard tier plan, and pay month to month. That is $79 * 100k = 7.9M per month in revenue. Again, huge over estimate, since I would guess 95% of the customers use the cheapest tier, and the largest companies most likely negotiate better than advertised fees.
Finally lets assume their BEST day is only about twice as good as their average day. This is probably overestimating their revenue by about 10x, at least.
That would mean they are bringing in well under $47.4M in gross revenue, on over $50M in fixed costs.
So in other words, even if black friday were half the days in the year, they still would lose substantial money. This is after 12 years of business.
It's unlikely they will ever turn a profit. If they were going to experience some kind of exponential growth to defeat this analysis, 12 years of the fastest growth in the internet have already gone by, so it seems unlikely going forward.