It's not bad to finance on huge, but you can definitely get better starts. There is a reason that HoF players usually roll for gems specifically!
Do they? Top 2 points game is tripple gold, couldn't look at many others, due to different patch version. And don't get me wrong, I would also take a quadruple gems start, but for Checker-Rush you need a plain Hill with a forrested plain Hill (or Gold-Mine-Hill) and tell me where you find that in combination with gems. Gems always come with green hills, at least in 99,5% of the cases.
Its not even that, 20 cities on standard settings cities would take gold, GLH, and a Shrine if settled early enough. Its easier to do this on either Huge or Marathon (due to either extra space or movement being quicker) and alot easier if both so it is just a more common problem with those settings.
You forget the Checker-Rush. With Checker-Rush you have 15 Cities by 1500 BC, that's about 150 turns. By that time, on Marathon, you barely have writing, not to mention cottages. All you have is the pillaged gold and a tremendous deficit. And it's not easier on Huge but more difficult, as distance is higher and maintenance also.
Converting hammers to commerce is much easer than the other way around.
If you reach pottery and writing, you can dig yourself out of any hole with adeqvate number of hammers.
Hammers -> workers -> cottages.
Hammers -> settlers -> cities -> libraries -> specialists
Catching up with commerce if you have good food/hammers is easy, compared to the other way around.
If you have commerce, you can get better techs, you can upgrade units too, but you can't do that much for increasing hammers/food.
I didn't say that commerce doesn't "count". I said that hammers/food is way more important than commerce.
I don't wanna offend you, but you're what is called a "keyboard jockey". You argument theoretically, without knowing the exact circumstances of a Huge Marathon Deity game. Problem is not growth, and problem is not production, problem is commerce. Try it out, take a high food high production start and Inca-rush 20 Cities till 1500 BC and tell me how you made it, I'd be glad if someone actually could show me.
To your arguments:
Hammers -> Workers -> Cottages
On Marathon, earliest possible time to reach cottages is 80 without any extra commerce, leaving you 70 turns to construct cottages. Each Cottage takes 15-20 turns so thats 3-4 cottages per city + 1 farm. 15 Cities, 10 commerce, 4 production, 1 GP Farm = 30-40 cottages = 60-80 commerce, let's say 80 because you built lots of cottages near rivers. 80 Commerce is exactly enough to support 10 cities with 1,5 workers / city + 1 unit guarding it, so even if you beelined cottages, you won't be able to support 15 cities by then. Don't believe me, test it, the math was done by me and verified by the data from my recent games, City Maintenance is 40 for 10 Cities not too far spread, Civic Upkeep is 20, and 20 is for the supply of the workers and the guarding units, with each city having a size of 3-5 which is exactly the 3-4 cottages + the farm.
That means, if you beeline cottages, you will be at 0% research +-0 GPT without writing or anything with 10 cities, with 15 cities (which you'll likely have with Checker-rush) you will lose tons of GPT. And, in this case, most of the workers weren't even built, they were stolen.
To your other argument:
Hammers -> Settlers -> Cities -> Libraries -> Specialists
15 Cities = 14 Settlers = 4200 Hammers + 21 Worker = 2500 Hammers + 15 Warriors = 450 Hammers = 7k Hammers base. 7k Hammers till turn 150 would mean about 50 Hammers / turn, just think about that number (!) . Oh, I forgot the Libraries... 1 Library with HC is 270 Hammers, lets say 10 of your 15 cities are commerce / research, thats addition 2700 hammers so it's 10k hammers meaning 65 Hammers / turn and that FROM TURN 1!
To say it in easy: You just won't have libraries till turn 150 on Marathon, because the research to writing already takes 150 turns without any extra-commerce, not even considering that you'd have to bring up 10k hammers for 15 cities with 20 workers 15 warriors and 10 libraries, which is IMPOSSIBLE! Considering what I've written before, about maintenance and upkeep, EVERY OF YOUR CITIES would have to be size 6-8 till then and work 1 farm rest cottages which again is IMPOSSIBLE!
I hope you understand that, but Huge Marathon Deity is simply another game, and Checker-Rush is totally different, to what you talk of. With normal Settings and another Civ, you will never ever have 15 Cities by 1500 BC, which is normal with HC on Marathon Huge, and maintenance and upkeep is so tremendously high, you don't have to believe me, test it yourself, you either won't reach 15 cities till 1500 BC or you won't reach pottery / writing, your normal concepts do not work, I do not tell lies, when I say, that I tried it, even with + Failgold and Cottagespam, without GLH + Shrine you won't have any research with an empire of that size at that time, plz try it and show me how it's done.