As a recent convert to Xero from Intuit QuickBooks Online (QBO), I am amazed by how clunky Xero is in comparison to QBO.  I would not have moved from QBO, if they hadn't broken my faith by failing to support me at a critical time.  Also, QBO support was much better, you could chat with a help agent in real-time, Xero support could not be in any way characterised as real-time.

There are costs in migrating from one cloud accounting platform to another, while I had a company migrate my QBO accounting data across to Xero, it was not exactly seamless.  It felt a lot like moving house, the removalists stacked the boxes in the rooms for me, but I was left to unpack things myself.  The cost is not very high (I paid around $800 to migrate two years of data from QBO, which is high enough to prevent churn, but not too high to lock in customers to an underwhelming product).

In short, if I had not had a "deal breaking" experience with Intuit, I would still be using it and would expect it to grow its market share.  The Xero monthly fee is around twice what I was paying for QBO, for an inferior product.

In short, I think that Xero risks being disrupted itself because its product is not very competitive (the last time I looked at the MYOB online it seemed to be like a Lego version of the PC version and it was not competitive with either Xero or QBO).  It presently has a lot of "mindshare", but could suffer from the Emperor's New Clothes.