Pace and means of acquisition matter.
I have a premium Mustang Mk Ia. I am nowhere near a 5/5 crew in it and especially nowhere near an ace crew despite hundreds of thousands of RP gained and dozens of hours in cockpit.

Look at the amount of RP needed to get maxed G/Stamina. Multiply these by 100 basically for SB/RB)
In my non-premium Bf109F4, maximum RP I can gain is 2500 per 15 minutes assuming I RTB and land safely, 2000 if I only die after 15 minutes pass. Calculate the amount of time that 2000/2500 RP/15 minutes takes to earn 5142 crew skill points (so 5142000 RP)
My premium british mustang can earn ~4500 RP/15 minutes without RTB, 5700 RP/15 minutes with RTB.
So roughly half the time the Bf109F4 takes me.
Difference between level 2 G/stamina vs 5/5 + expert is=


(I removed G suit for these tests. Used F4U-4 because it’s not gonna stall from AoA nor rip)
2+2 Noob crew passes out after ~ 20 seconds (generously rounded up) at 5.5Gs
5+5 Expert crew can sustain 5.5G indefinitely.
With an ace crew, you could even do 6.1G before exceeding your maximum tolerance.
Time it takes to go from 2+2 to 5+5 with bf109 is (2571*2-(22+64+110+160)*2)*100 = 443000
Bf109F4 no RTB (/2000 * 15 / 60): 55 hours
Bf109F4 with RTB: 44 hours
Mustang Ia no RTB: 24 hours
Mustang Ia no RTB: 19 hours.
Now, you do get to save crew slot and reuse it so this is a once per crew slot grind.
Still, given the way levels require more and more RP to unlock and the sheer amount of time even with what is perfect gameplay (Every 15 minutes we get 1050 or higher score and never ever die), it takes an absurd amount of time to be able to fly your plane on par with your opponents doing the exact same maneuvers at the exact same conditions in the exact same plane. Even a premium plane with very high economic modifiers for a rank 3 is at a significant disadvantage for a LOT of matches.
And we havn’t even spoken of ace crews yet. I cannot provide data comparison there as I am yet to unlock one. However, I recall something like 750k RP needed for my Mustang Ia to unlock an ace crew, and I make at most ~20-23k RP per hour doing my best (4500 or 5600 RP per 15 mins x 4).
As for the battlepass -
The battlepass itself is impossible to progress unless you’re willing to give up your autonomy and fun for ~2-3 hours each day chasing absurd tasks that your tech tree and favourite BR range may not even be able to complete or is completely incompatible with how matches are done in your favourite game mode.
If I was going for BP tasks, I would be unable to play prop tier ASB due to how the daily 2 tasks are structured (you cannot start a new BP task without leaving the lobby you’re in, and the lobby you’re in may take 90-120 minutes to conclude - so you can end up more than satisfying medium/hard task for a day and not get credit due to only playing a single lobby). Even more so, a lot of the challenges outright don’t allow completion in ASB.
“You can obtain it in-game” only counts if the means of acquisition are reasonable and accessible at the level of play expected. Like, 40 hours to get an expert crew would be fine if it only mattered for jets, but it very much matters as low as 3.0-5.7 especially if you fly aircraft that rely on descending spirals and high speed scissors to win dogfights.
Starting a new tech tree is legit suffering because of how crew skills are implemented.