Honest companies are expected to retain their users by offering the best service they can provide and not by actively locking them in and making it hard to switch to a competitor. Google, for example, lets users easily download all their contacts, bookmarks, photos, emails, and other personal data though Google Takeout.
[Update: Smoking Gun] WhatsApp Is Blocking Telegram Links In Its Android App was written by the awesome team at Android Police.
Source: Andriod Police