On average an iPhone receives 4-5 years of iOS updates and support, compare this to any AndroidOS phone, this is great value for an initial higher cost of purchase.
iPhone (A1) released 2007, discontinued in 2008 and dropped 2011.
iPhone 3G (A2) released 2008, discontinued in 2010 and dropped 2012.
iPhone 3GS (A3) released 2009, discontinued in 2012 and dropped 2013.
iPhone 4 (A4) released 2010, discontinued in 2013 and dropped 2014.
iPhone 4S (A5) released 2011, discontinued in 2014 and dropped 2015.
iPhone 5 (A6) released 2012, discontinued in 2013 and dropped 2016.
iPhone 5S (A7) released 2013, discontinued in 2016 and dropped 2017.
iPhone 6 (A8) released 2014, discontinued in 2018 and dropped 2018.
iPhone 6S (A9) released 2015, discontinued in 2018 and dropped 2019/20 (predicted).
iPhone SE (A9) released 2016, discontinued in 2019 and dropped 2019/20 (predicted).
iPhone 7 (A10) released 2016, discontinued in 2019 and dropped 2020/21 (predicted).
iPhone 8 (A11) released 2017, discontinued in 2020 and dropped 2021/22 (predicted).
iPhone X (A11) released 2017, discontinued in 2018 presently supported and dropped 2023/24 (predicted).
iPhone XR (A12) released 2018, discontinued in 2019 (predicted) presently supported and dropped 2023/24 (predicted).
iPhone XS (A12) released 2018, discontinued in 2019 (predicted) presently supported and dropped 2024/25 (predicted).
iPhone ? (A?) released 2019