The Number of Citizens Leaving (Renouncing) Versus Coming (Naturalizing) is Just a Speck
Much has been made about the number of citizens who have been renouncing their U.S. citizenship over the last few years. In historical terms, it is a relative explosion. See, earlier post – The 2014 Third Quarter Renunciations Is probably the New Norm –
However, compared to the 
number of lawful permanent residents (LPR) who are leaving the U.S., the number is relatively small. See, earlier post The Number of LPRs “Leaving” the U.S. is 16X Greater than the Number of U.S. Citizens Renouncing Citizenship
On a related post, the question was raised –What are the Number of LPRs who Leave U.S. Annually without filing Form I-407 – Abandonment?
However, the number of individuals who wish to come to the U.S. to become citizens is far in excess of the number who are renouncing their citizenship. 
According to the USCIS, there are about 700,000 individuals annually who become naturalized citizens. In the year 2008, there were more than 1 million naturalized citizens. See table:
Compare these numbers to just about 3,000 annually of individual who are renouncing their citizenship.
Of course, everyone has their own story and reasons for either coming or going, but in relative terms, those who find it desirous to renounce citizenship (at least in absolute numbers and relative terms) represent a small speck (less than 1/2 of 1 percent), compared to those who are becoming naturalized citizens.
Finally, for anyone who wishes to become a naturalized citizen, they must be aware they cannot “reverse” the decision without having potentially adverse U.S. tax consequences. See, Why a Naturalized Citizen cannot avoid “Covered Expatriate” status under IRC Section 877A(g)(1)(B)