There are alternative arguments. Just as comparing Latin to English has been criticised, comparisons with Germanic languages can be overemphasised. 'To' is sometimes followed by an infinitive and sometimes by a gerund, so it doesn't have a single fixed use, which is the argument put forward by the people who wish to distinguish the preposition from the particle/infinitive marker, though particles are a category I don't have much time for personally. Pragmatically, I call it a preposition, but the evidence does suggest that there is more to it than a simple preposition, IMO.
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