The support is very poor yet. What about built-in browser in a 5 years old smartphone? Don't use new technologies, wait for 5 or 10 years until they are suppor

The support is very poor yet. What about built-in browser in a 5 years old smartphone? Don't use new technologies, wait for 5 or 10 years until they are supported everywhere. Flexbox is good enough for 99% of cases.