It would be interesting to see the sales figures for the i4 and the Model 3 and see what percentage of each vehicle is purchased vs. leased.
BMW's have been a car that you want to lease rather than buy for a couple of decades now due to the reliability issues and costs of repairs once the cars are about out of warranty. Maybe the i4 will be more reliable than their ICE vehicles but I wouldn't hold my breath.
Tesla is taking market share from the upscale German car companies, that is not in dispute. They are all scrambling to build EVs to compete, but are falling short from EV and tech standpoint. BMW should have built a car ground up as an EV instead of using the 3/4 platform. Then there would be less compromise. The result is a mix of 2 drivetrains and suffers beause of it.
There are plenty of well documented Tesla issues. Missing brake pad? That's just crazy. There are also plenty of BMW owners who say their cars spend more time in the shop than on the road. Repairs and services are costly. I live in Silicon Valley; there are tons of German cars here. And yes, 3 year leases are the norm. There is a reason for it.
If you told me BMW was building an $80K (and up to over $100K) M Series electric car, I would have bet they would deliver an incredible car, but the results are far from that. Heck, in price and weight, this car is close to a Model S. BMW didn't even deliver an M with more performance than a 5 year old Model 3.
Say what you will, but Tesla owners are far happier with their cars, warts and all, then BMW owners.
In the end, each to their own. It's your money. I like them all and worthy competitors make for better products for the consumer.