It's not so long now to wait for Joomla 4 to enter the market. Presumably, Joomla 4 will be released in the 1st quarter of 2020. At the same time, Joomla 3.9 will be supported for 2 years and this is quite a sufficient period for reflection and transition to a new platform. It is important to understand that Joomla 4 will only work on PHP 7.
Although Joomla has improved over time, it has been developed using technologies from a decade ago. To date, Joomla is no longer in line with modern technology.