@Emberguard - there is a big difference between what you & I are saying.
Yours is a rather elitist attitude, coming from a hyperlevel-GB play point of view. This game can be played exceeding well using any & all GBs without exclusively rushing a GB to level10, hyperleveling GBs, or having Arc80s hand you most everything. At least 90-95% of all players aren't playing your preferred way, you know. The Arc is a very useful GB at every level. Even knowing it could take 4-6 months (or more) to raise it to level 10 should never be a deterrent to not getting it.
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People don't usually start donating until around lvl 16 outside of FP swaps."
... Yes they do. Hoodies & friends list players donate regularly at every level to the Arc & every other GB. Hyperleveled Arcs may ignore donating, as the perceived meager payout isn't worth their time. But a ton of other players definitely find those steady rewards (even for spots #4-5) quite useful. Don't discard all those fp donations as trivial to the leveling process simply because spots 1-5 weren't taken at the Arc80's 1.9 fp rate.
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Most players that build an Arc focus purely on raising the Arc."
.... Perhaps true of players you know, but entirely untrue of most of players. Of the many players with an Arc, a minority are hyperleveling it (my source is foestats.com, can see folks with GBs relative to levels of the GB amongst all players in each world). Of those simply bringing it to level 10, I don't see any data supporting the claim that most focus purely on that either. My anecdotal evidence of looking at all my hoodies GBs these past many months suggests otherwise - most are leveling it alongside other GBs being raised too.
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If you're staying for a few years then go for it. But if you've just started and plan to quit at the time the Arc would be finished being raised then you'd probably be better off concentrating on actually advancing through and beating the game."
... Exactly how long do you think it takes players to raise Arc to 10 without a large fp/day income or Arc80s doing the job? Beating the game as you've defined it is "advancing through" the Ages to the end. How long does that take - at least 2-3 years if that's your main focus & you're not unwisely trying to rush? Can't be less than that, I figure. So if you're just starting out or your fp/day income isn't high by your standards (above what # you don't specify but you seem unimpressed with OP's current 100 fp/day), you feel it'd take at least a couple years to get Arc to 10. And that an Arc at anything less than 10 wouldn't be worth it at all, I suppose.
Gosh, you honestly have no idea (or have forgotten) how the myriad of interrelated aspects of this wonderful game can be utilized to their fullest.
Perhaps giving you some perspective on what common folks can obtain in this game with some practice & study will help you. ...
I've been playing in my 1st (main) world ~13 months. Never been in a guild other than just me (so can do GE). After a couple months, I knew I liked the game but I've no idea for how long I'd play it (still don't). Currently, I'm in Colonial Age with 1.6M rank points, 88 fp/day income (includes 24 daily freebies but doesn't include any BG bonus rewards that may or may not happen). I've been able to fully complete every Event & complete GE4 every week ever since Iron Age, when playing for ~2 months.
Great buildings' levels:
10 for Zeus, CoA, LoA, RAH, CF, DT, SMB, Blue Gal
9 for TOR
5 for Seed vault
2 for Habitat
1 for Himeji castle
(FWIW, I don't have an Arc due to my playstyle/availability. My time's been split between building up my main & multiple GE diamond cities. As such, I'm unfortunately only checking for GB donations opportunities infrequently in main game. Improvement of GB donation rewards is the primary Arc benefit. If I'm not doing it consistently yet, the Arc is wasting my space).
My 1st higher level GBs - CF & DT - were obtained within 1st 1-2 months of playing (only had zeus, LOA & babel GBs). At that time, I was in IA with maybe 26-28 fp/day income (that includes the 24 daily freebies). Spent fps to purchase DT goods but got CF the hard way via goods from my city buildings/trading up in the market - took about 4 weeks of work. I've always raised GBs side by side for the most part - only one that well outdistanced the others to level 10 was CF. I easily could afford purchasing the high level GB goods for DT, SV, BG, habitat, & himeji - all for the competitive standard fp cost in my world (no special arrangements or discount prices). Blue galaxy was obtained about 3 months ago. The 7 other GBs currently at level 10 were already at that level or at worst 8 by the time I got BG , thus the potential BG bonus rewards were nice but not the primary source of fps. And 3 months ago my fp income was around 50-60/day.
You look at fp/day income as a limiting factor in whether or not someone should even consider getting higher level GBs like the Arc. It's not. If it was, how the heck could I have the GBs I have, when I got them & leveled them as high as I did - all within 13 months with a relatively low fp daily income? I'm not special. I don't play all day. I work full time & never check my game while working. I have a life outside the game. I don't set a timer to remind me to collect buildings. I often don't even collect on time. I'm not throwing real money at the game (did spend a small amount very early on - turns out I didn't need to, as learning a bit more got me what I wanted instead of needing cash). So, how did I do it?
The answer? I understand how to make great use of everything the game offers. Glad I never listened to advice like yours.