While it's one of the primary complaints (after purchase), the market would seem to suggest that people prefer smaller/thinner phones in terms of purchasing decisions.
Sounds like Pentagram Monster series. The one I have with 4100mAh battery lasts for over 20 days, if I'm not using it heavily. And while it is heavier than typical smartphones, it's only about 1cm thick. As far as I know there's also a newer model with 6000mAh battery.
Of course it's been a complaint forever but how many flagship phones with great battery life do you count? My point is that More battery-hungry widespread applications = More pressure on manufacturers to answer to those complaints.
It's also been a complaint forever that people's parents, friends, children, and selves keep dying. And yet somehow that hasn't translated into enough market pressure to make them all immortal.
Of course in reality the market pressure for protection from death is much greater than the market pressure for improved battery life while seeing weaker results in the market. Your battery life is not a market pressure issue.