we certainly have turned the corner...and are probably ready for take-off . The growth is diversified and broad - and nothing seem to take it down - be it global meltdown or local factors - so maybe we are on take-off already - but we need to reach 8-10% annual gdp growth rate - and that can only be possible if we invest heavily in infrastructure or strike some minerals.
I reckon by 2020-2022 we will be ready for take off - with universal electricity coverage (from 60% now to 100%), maybe 20,000-30,000km tarmac road (out of 65,000 classified road networks), lapset & turkana oil, SGR all the way to Malaba, all these special economic zones & industrial parks, high growth in construction & real estate with at least 15 cities(thanks to devolution) -from current 5 (nbo,msa,eld,ksm,nakuru), doubling or tripling of formal retail & wholesale through expansion of supermarkets & malls (from 14-18% now to something close to 40-50% like in South Africa), demographically transition to having more adults than children (right now maybe 1/3 of counties have achieved this), more financial deepening thanks to mobile money & real growth of credit ( some estimate 300-500% credit growth is possible by 2020), accelerated expansion & modernization of gov services - universities & health.
In summary I'd say the earliest we can take off is 2020...latest 2022.