Learn Russian: Хорошая коллекция не может создаваться быстро. - A good collection cannot be created quickly.

While -ся often makes a verb reflexive (like washing oneself), it is also used to create a passive meaning with imperfective verbs. Here, the collection isn't creating itself; it is being created by someone else. This is a very common way to express the passive voice in Russian.

Why use the imperfective создаваться instead of a perfective verb?

The sentence focuses on the ongoing process of building a collection. Because it says this process cannot happen быстро (quickly), we use the imperfective aspect to emphasize that creating it takes a continuous, extended amount of time.

Why is the verb создаваться in the infinitive form?

It is in the infinitive because it directly follows the conjugated helper verb может (can). Just like in English where we say 'cannot be created', the second verb in the pair stays in its base infinitive form.

Could we just use the active verb создавать (to create) without the -ся?

Not with коллекция as the subject. If you used the active verb создавать, you would need a person as the subject, like 'Someone cannot create a good collection quickly.' Because the collection is the grammatical subject here but is receiving the action, we must use the passive -ся form.