The current crop of players are just starting to hit their prime years and have a lot of experience under their belt. Just got to look at the last calendar year where Bangladesh beat India, South Africa, Pakistan and had decent runs in the Asia Cup and WC in ODIs.
A young/unfancied Sri Lanka team managed to win the WC so why not Bangladesh?
Bangladesh will win a cricket world cup within the next decade.
No they won't.
There's no chance they'll win in 2019, and while the conditions will be more favourable in 2023, that's still a big ask. I'm not saying they can't become more of a force than the likes of SL, and the Windies once their talismanic figures retire, and maybe even Pakistan, but to overcome the whole lot - plus Australia, India and even England - will be a heck of a feat.
SA haven't won one - and that's with ABDV, Amla, du Plessis, Smith, Kallis, Pollock etc. So what makes Bangladesh able to?*