Laudator Temporis Acti

There has been much debate recently about the antecedent of a pronoun in a speech delivered by President Obama on July 13, 2012, in Roanoke, Virginia:

If you were successful, somebody along the line gave you some help. There was a great teacher somewhere in your life. Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges. If you've got a business—you didn't build that. Somebody else made that happen. The Internet didn't get invented on its own. Government research created the Internet so that all the companies could make money off the Internet.

In the apodosis of the conditional sentence ("you didn't build that"), does the pronoun "that" refer back to the noun in the protasis ("if you've got a business"), or is the antecedent "roads and bridges" in the preceding sentence?

I have no opinion to express on the interpretation of the President's speech, but the controversy does remind me of some passages from Latin literature which claim that a man is the architect of his own fortune.

Plautus, Trinummus 363 (tr. Paul Nixon):

For I tell you, a man, a wise man, moulds his own destiny.

nam sapiens quidem pol ipsus fingit fortunam sibi.

Cicero, Paradoxes of the Stoics 5.34 (tr. H. Rackham; context = only the wise man is free):

...whose enterprises and courses of conduct all take their start from himself and likewise have their end in himself, there being no other thing that has more influence with him than his own will and judgement? to whom indeed Fortune, whose power is said to be supreme, herself submits—if, as the wise poet said, she is moulded for each man by his manners.

cuius omnia consilia, resque omnes, quas gerit, ab ipso proficiscuntur eodemque referuntur, nec est ulla res quae plus apud eum polleat quam ipsius voluntas atque iudicium? cui quidem etiam quae vim habere maximam dicitur fortuna ipsa cedit, si, ut sapiens poeta dixit, suis ea cuique fingitur moribus.

Pseudo-Sallust, Speech to Caesar 1.2 (tr. J.C. Rolfe):

But experience has shown that to be true which Appius says in his verses, that every man is the architect of his own fortune.

sed res docuit id verum esse, quod in carminibus Appius ait, fabrum esse suae quemque fortunae.

Cornelius Nepos, Life of Atticus 11.6 (tr. J.S. Watson):

He accordingly made it appear, to have been truly said, that "Every man's manners make his fortune."

itaque hic fecit ut vere dictum videatur: sui cuique mores fingunt fortunam hominibus.

For more parallels see Renzo Tosi, Dictionnaire des sentences latines et grecques, tr. Rebecca Lenoir (Grenoble: Jérôme Millon, 2010), #96 (pp. 112-113), where however on p. 113 the reference to "Fulgence, Exposio Virgilinae continentiae" should (I think) be corrected to "Fulgence, Expositio Virgilianae continentiae".

Thanks to the friend and benefactor who gave me a copy of the French translation of Tosi's dictionary of Latin and Greek proverbs, a most welcome addition to my library. "If I've got a library—I didn't build that. Somebody else made that happen." Or, as Ben Jonson wrote in An Epistle to a Friend, lines 4-6:

You have unto my Store added a Book,
On which with profit, I shall never look,
But must confess from whom what gift I took.