Apple currently generates $50 Billion annually in services revenue from ~1 Billion userbase, which is $50 per user per year, and this excludes the passthrough portion of app revenue (eg the 70% that goes to 3rd party developers for 3rd party apps is not included, only Apple's ~30% cut is) so the gross amount of revenue per user is actually much higher than $50.
So with a long term view a Tesla userbase of 50 million cars generating $50-$100 a year each on average in app revenue would be $2.5-$5 Billion revenue per year. If it is anywhere near Apples services gross margins (70%) that would translate to $1.75 - $3.5 Billion in Gross Profit for Tesla.
yes, a 50 million userbase of Teslas may take a while to build (we are talking ~10 years) so likely not a big earner in the short term, but something to think about long term even if it does pale in comparison to annual revenue/profits from upfront Auto & Energy sales.