My hypothesis are:
1) Not enough battery suppliers to get "slim Grade A" 5000mAh capacities to flagships for all vendors. If Apple, Samsung, LG, HTC, LeMoto, Huawei, Xiaomi, OPPO, Vivo, OnePlus, etc target the "slim Grade A" 5000mAh capacity, then, the suppliers will jack-up the price per unit due to high demand.
2) "Slim Grade A" battery is not cheap. Hence, if put it into flagship, the SRP will increase further.
3) If "Slim Grade A" battery inside flagships, then, the next flagship of the same model may not be in interested for existing owner becoz the current "Slim Grade A" battery can last for 3 years serviceability. So, manufacturers will loose sales every quarters.
4) There are alternatives to energy. Powerbanks, built-in battery casing, smart software algorithm "power-saver" and car chargers.... Manufacturers have the mindset that no need to focus or spend money on "slim Grade A" battery because of these accessories/alternatives. Beside, this will allow other vendors to sell these accessories and give "opportunity" or options to phone owners who want slim & light design (cough-cough Apple ...) to enjoy their slim & light phones.
5) Manufacturers rather spend money & R&D on camera, SoC and form-factor as the "X-factor" to attract buyers. Battery is just a surplus if manufacturing cost permits.

The best "role model" to the ultimate form-factor flagship is Xiaomi by offering 4000mAh for below 5.5" screen with so-called "flagship" camera, "flagship" SoC" and "flagship" form-factor. Only the experience is sub-par "flagship" to certain potential buyers. OnePlus comes second (due to almost affordable) followed by Sammy's current flagship with 3500mAh battery. Motorola Moto Z Force Droid is also 3500mAh.

If Apple 8/X/Decade Plus to have 5,000mAh Slim battery, then, I'll buy more Apple stock market shares...LOL...
[attachmentid=8458322]

Just my 2 cents based on observations...

my point is they offer you choices. kenot offer everything into one device, because of $$

Huh...?
[attachmentid=8457613]

My hypothesis are:
1) Not enough battery suppliers to get "slim Grade A" 5000mAh capacities to flagships for all vendors. If Apple, Samsung, LG, HTC, LeMoto, Huawei, Xiaomi, OPPO, Vivo, OnePlus, etc target the "slim Grade A" 5000mAh capacity, then, the suppliers will jack-up the price per unit due to high demand.
2) "Slim Grade A" battery is not cheap. Hence, if put it into flagship, the SRP will increase further.
3) If "Slim Grade A" battery inside flagships, then, the next flagship of the same model may not be in interested for existing owner becoz the current "Slim Grade A" battery can last for 3 years serviceability. So, manufacturers will loose sales every quarters.
4) There are alternatives to energy. Powerbanks, built-in battery casing, smart software algorithm "power-saver" and car chargers.... Manufacturers have the mindset that no need to focus or spend money on "slim Grade A" battery because of these accessories/alternatives. Beside, this will allow other vendors to sell these accessories and give "opportunity" or options to phone owners who want slim & light design (cough-cough Apple ...) to enjoy their slim & light phones.
5) Manufacturers rather spend money & R&D on camera, SoC and form-factor as the "X-factor" to attract buyers. Battery is just a surplus if manufacturing cost permits.

The best "role model" to the ultimate form-factor flagship is Xiaomi by offering 4000mAh for below 5.5" screen with so-called "flagship" camera, "flagship" SoC" and "flagship" form-factor. Only the experience is sub-par "flagship" to certain potential buyers. OnePlus comes second (due to almost affordable) followed by Sammy's current flagship with 3500mAh battery. Motorola Moto Z Force Droid is also 3500mAh.

If Apple 8/X/Decade Plus to have 5,000mAh Slim battery, then, I'll buy more Apple stock market shares...LOL...
[attachmentid=8458322]

Just my 2 cents based on observations...

Forget about huawei.. .. I sold off my mate 8 for P2. The mate 8 battery is useless la... . when I play game it will drop 10 % per hour with the charger plugged in. After one week of use I went to complain in the sc and they gave me a new unit but battery performance still bad.... give up la

Forget about huawei.. .. I sold off my mate 8 for P2. The mate 8 battery is useless la... . when I play game it will drop 10 % per hour with the charger plugged in. After one week of use I went to complain in the sc and they gave me a new unit but battery performance still bad.... give up la

Actually, once manufacturer exceeds 5.7", they can already fit in 5,000mAh battery easily and yet they just fit in 4,000mAh.  I also sigh.....

Today I'll try to use my phone naked, taking out the stupid soft silicone back cover as I have to clean it every day. It is not as slippery as I thought now contemplating taking out that screen protector, a finger print magnet

Today I'll try to use my phone naked, taking out the stupid soft silicone back cover as I have to clean it every day. It is not as slippery as I thought now contemplating taking out that screen protector, a finger print magnet

Just be careful,  i have few kwn who like to use the phone naked, 

Now after having bad exp of dropping their phone n spend xxx amount to fix.  Now they prefer the phone in a case+tempred glass

2 months passed by and the current price still above RM1K...