NEW YORK (TheStreet) -- Apple ( AAPL) closed Tuesday under $570. A little earlier in the day, it touched below $550. In the days prior to its last earnings call in April, Apple shares hit a low of $555.This recent swoon, after moving from $360 in November to an all-time high of $644, has brought out a chorus of Apple-worrywarts. They are saying this is just the start of a broader pullback. They're saying this is due to investors who are worried about carriers pulling their subsidies on future iPhones. Any pullback in Apple shares also seems to bring out the concerns about whether the largest company by market capitalization can still keep growing. The other day, I spoke with a good friend of mine who worried about Apple's stock that: "Steve's no longer there and their markets are brutally competitive."