I think posting this will be helpful, as some people were discussing initial volume sales for popular series (this is based on Oricon data so it only covers initial volumes from 2008 onwards):
【Sales of 1st volume】
│Week 1│ Week 2| Week 3| Week 4| Week 5┃Total sales┃ Release date│Series
│121508 (3)│208375│261509│323689│361695┃1,435,358 (*899)┃2012/11|Assassination Classroom 1
│*31428 (7)│------│------│------│------┃*,722,894 (*770)┃2012/06|Haikyuu!! 1
│154676 (7)│192852│214633│232004│247981┃*,503,*** (*399)┃2009/01|Bakuman 1
│*20445 (3)│*32878│*35709│*45784│------┃*,500,417 (1200)┃2009/04|Kuroko no Basket 1
│*71367 (4)│*89378│107990│139657│------┃*,373,430 (*228)┃2013/04|Shokugeki no Soma 1
│*71575 (6)│******│101801│137449│157439┃*,233,330 (**69)┃2014/11|Boku no Hero Academia 1
│*69177 (6)│*86567│109701│129509│139756┃*,161,360 (**48)┃2008/11|Toriko 1
│*30802 (3)│******│******│*58160│*79985┃*,*79,985 (**31)┃2014/04|Ginga Patrol Jaco (Total 158,837)
│*47482 (3)│*78852│------│------│------┃*,*78,852 (**10)┃2014/04|Ginga Patrol Jaco Special Edition
│*51163 (3)│*90847│104836│114358│121788┃*,121,788 (**31)┃2009/07|Beelzebub 1
│*54618 (3)│*93014│105001│109581│------┃*,109,581 (**24)┃2009/12|Ane Doki 1
│*15472 (3)│------│------│*49965│*61178┃*,*98,639 (**66)┃2009/10|Medaka Box 1
│*48495 (7)│------│------│*68710│------┃*,*68,710 (**28)┃2008/08|Nurarihyon no Mago 1
│*44215 (5)│*59205│------│------│------┃*,*59,205 (**12)┃2012/01|Kagami no Kuni no Harisugawa 1
│*21855 (6)│*24390│*50167│------│------┃*,*50,167 (**20)┃2014/02|Isobe Isobee Monogatari 1
│*45317 (5)│------│------│------│------┃*,*45,317 (***5)┃2012/05|Nisekoi 1
│*40644 (7)│------│------│------│------┃*,*40,644 (***7)┃2008/08│Double Arts 1
│*38631 (5)│------│------│------│------┃*,*38,631 (***5)┃2014/06|Illegal Rare 1
│*38128 (4)│------│------│------│------┃*,*38,128 (***4)┃2015/06|Black Clover 1
│*35058 (4)│------│------│------│------┃*,*35,058 (***4)┃2012/10|Koisome Momiji 1
│*34116 (6)│------│------│------│------┃*,*34,116 (***6)┃2012/09|PSI Kusuo Saiki 1
│*23980 (7)│*33845│------│------│------┃*,*33,845 (**14)┃2008/08│ Bari Haken 1
│*32023 (7)│------│------│------│------┃*,*32,023 (***7)┃2011/07|Magico 1
│*31899 (7)│------│------│------│------┃*,*31,899 (***7)┃2012/06|Pajama na Kanojo 1
│*15421 (3)│*24640│------│------│------┃*,*24,640 (**10)┃2009/10|Akaboshi 1
│*12384 (3)│*20617│------│------│------┃*,*20,617 (**10)┃2010/06|Kiben Gakuha, Yotsuya-senpai no Kaidan 1
│*19924 (4)│------│------│------│------┃*,*19,924 (***4)┃2014/09|Hinomaru Zumou 1
│**9216 (3)│*18967│------│------│------┃*,*18,967 (**10)┃2009/05│ Bokke-san 1
│*14496 (4)│------│------│------│------┃*,*14,496 (***4)┃2010/02|Hokenshitsu no Shinigami 1
│*12287 (5)│------│------│------│------┃*,*12,287 (***5)┃2009/02|Inumaru Dashi 1
│**8529 (4)│------│------│------│------┃*,**8,529 (***4)┃2010/02|Super Dog Lilienthal 1
│**Didn't rank (5)│------│------│------│------┃*,**, (***5)┃2011/01|Enigma 1 ※Less than 22,870
│**Didn't rank (4)│------│------│------│------┃*,**, (***4)┃2010/11|Oumagadoki Zoo 1 ※Less than 17,368
│**Didn't rank (3)│------│------│------│------┃*,**, (***3)┃2011/12|Kurogane 1 ※Less than 18,142
│**Didn't rank (7)│------│------│------│------┃*,**, (***7)┃2013/03|Cross Manage 1 ※Less than 18,131
│**Didn't rank (3)│------│------│------│------┃*,**, (***3)┃2008/05|Psyren 1 ※Less than 18,471
│**Didn't rank (5)│------│------│------│------┃*,**, (***5)┃2013/09|Soul Catcher(s) 1 ※Less than 21,512
│**Didn't rank (4)│------│------│------│------┃*,**, (***4)┃2013/07|World Trigger 1 ※Less than 18,384
It's hard to predict future success based only on the initial sales. From this list, Ane Doki, Kagami no Kuni no Harisugawa, Double Arts and Pajama na Kanojo got cancelled in less than one year, and Magico only lasted one year and a half, while World Trigger grew and became a success with no end in sight, Psyren lasted three years and Soul Catcher(s) is alive after more than two years.