Not offering a buy-option basicly means the lease should be classified as an operating lease, and remains on the balance sheet of Tesla.
I can think of 2 likely scenarios where they are not offering financial leases (=with a fixed buy back option).
1/ They think they can make a profit on the sale at the end of the contract. If they can convince clients to take a lease where the asset it written down to x, and at the end of the contract it will be worth y>x, Tesla will make additional profit.
2/ They want to manipulate their EBITDA. Accounting for operating leases is a bit funny for the lessee, since the asset is written down in the lessee's P&L, but over the lease its lifecycle it's a cash flow neutral operation, Tesla "bought" the asset to lease it to the customer, after which the client pays monthly bills which include depreciation. This has a favorable effect on EBITDA, but usually a negative effect on debt (=Tesla has to finance the transaction).
For companies that are purely active in operating leases, the classic EBITDA metric is useless and is not used. I'm not sure whether Tesla makes this distinction somewhere in its reporting?
If my explanation is confusing, you can look at financial statements of ALD, a huge company exclusively active in operating leases:
https://www.aldautomotive.com/invest...-communication