Buying a new (crappy, what do you expect for 50 Dollars?) phone because your perfectly working one isn't supported anymore is NOT satisfying and not a solution.
Windows XP is actually a very nice example. According to Wikipedia it came out in 2001 and got constant (you can complain about the quality or bring up other complaints) updates until 2014. It's rather amusing that you bring up Windows XP as a _counter argument_ to decent updates. Most phone manufacturers have a hard time updating their devices for 1.5 to 2 years, let alone 13.
I feel that you're a bit lost. You want to save a bit of money ($50 is your example) when you purchase a new device because if it's becoming vulnerable due to a crappy manufacturer/vendor you can always .. get a different one for the same price?
Ignoring that this doesn't make sense, you're also hurting the 'herd immunity'. This argument of yours is comparable to anti-vaccines discussions. "I want .." vs. "The general public would benefit if this would be the case". I know what Kirk and Spock would decide, but you're entitled to have a different opinion, of course.