Agreed. But I imagine if you buy something like the total stock market index (https://investor.vanguard.com/mutual-funds/profile/VTSMX) that Lyft would be included, since they try to buy every public US stock.
[0]: https://www.reuters.com/article/us-snap-russell/ftse-russell...
http://www.crsp.com/indexes-pages/returns-and-constituents
Not sure about Lyft, of course.