Why won't the new iPhone have 5G?

5G is coming out next month. Why won't iPhone have it?

Does it need to be a race to be the first to have it?

I've heard 5G is very dangerous, so i won't be getting it.

Initial 5G specs will not be released until 2019
at which time cutting-edge phone and phone component mfgs can be secure in how the standard will be implemented in hardware.
Until then
every implementation is a sort of beta-test
intending to prove that the technology works
but not certain that the technology will be implemented in exactly that way
(since the formal standard has not been released yet).

It's just too cutting-edge at the current time.

However
also
when next years I-phones are put on the market
they will be 5G capable
and of course everyone will rush to buy them.

SO: they are also looking toward a big increase in sales next year because of the availability of 5G next year.