[virtualwhys]

Migrated a Scala 2.8(!) era codebase to Scala 3.

As OP explains, macros and abstract type projections tend to be the biggest pain points in complex applications; otherwise, with Scala Rewrite tool it's pretty straightforward.

I think it's more inertia than anything else that more Scala 2 companies don't migrate.

Unpopular opinion, but setting a Scala 2 sunset time would spur companies into action :)

As it stands Akka (previously Lightbend, previously TypeSafe) is the maintainer of Scala 2, and derives part of its revenue from Scala 2 support contracts so there's even less incentive to migrate when there's no EOL date as Python 2 (eventually) had.

[hocuspocus]

While a bit late to the party, Akka on Scala 3 is perfectly viable nowadays, and they have a couple employees contributing to Scala 3.

The bigger issue comes from Databricks being the biggest Scala Center sponsor while holding the entire ecosystem back, for instance with their managed Spark runtime still on 2.12.

[rat87]

As someone who has done a couple of python 2 to python 3 migrations I'm still surprised that there isn't someone big selling support/security patches for python2. There must be a lot of giant corporate python2 code bases that were a lot harder to port and where it was much less acceptable to find random 2to3 bug I'm production then the QA and build system codebases I ported