It's unfortunate that you always have to pay for the updates, as logic pro, from 2013 to date, has not charged anything additional for the updates and they have been quite complete.
I think the small number of cases where updates are free is because (A) the business is extremely rich and successful because of its other products (Apple) or (B) they had a very lucky start which compounded over the long term so they don't really need to charge for updates anymore (FL). Software engineering is extremely costly, if you don't know that industry you would be surprised how much money even the more trivial bug fix costs, just in term of salaries...
I know what you're saying but Ableton is a much smaller company and personally I'm happy (I guess) to pay for upgrades. Logic Pro is almost a loss leader for Apple as it's MacOS only, it sells a lot of Macs.
On one hand you have Apple, a mega billionary corporation, on the other hand you have Ableton with thousand times less income. They have to eat somehow
