For me, a larger part than "cost of lock-in" is the "hacker spirit", the curiosity to understand how it works.
Sure, I can pay google or fastmail to host a mailserver for me, but that deprives me of the joy of configuring and updating dovecot/postfix/etc, writing custom backup scripts, writing my own anti-spam tooling, etc. I want to know how all those pieces work.
Sure, I can pay kagi to search its index of webpages for me, but that deprives me of the joy of creating and running a botnet to index webpages, storing 100s of terrabytes of scraped data, and writing my own search code.
Targeting hackers is indeed a sucker's game.