They both began with having a single use but overtime have become multi-functional.
Those of us with smart phones may find that we no longer have use for: mp3/4 players, cameras, torches, home telephones, address books, calendars, calling cards for overseas calls, photo albums or even a laptop.
Instagram has done the same but instead with other platforms. It hasn’t made them obsolete but it has given them a rival and in some cases has become more dominant.
Instagram offers an alternative to:
Snapchat with insta-stories
YouTube with IGTV
Affiliate links on blog posts with the swipe up feature.
Blog posts with guides (but even just a feed carousel and a long caption is pretty similar to a blog post)
TikTok with Reels
Instagram is no longer just a photo sharing app in the same way that mobile phones are no longer just for making calls.