I don't feel like it does vendor lock-in. It only really locks you into using utility CSS, but you can "eject" at any time by throwing out the framework and keeping your compiled file with utility classes.
And then... you'll keep two wildly different CSS styles for the same project? That doesn't seem reasonable.
Vendor lock-in doesn't mean that you can't get out at all, just that it has significant cost. Maintaining both Tailwind and another CSS framework/philosophy/classes in the same project has a significant cost.
Yes, but this is the same kind of cost as, say, switching from an OO to a functional design, and we don't normally refer to "choosing to use OO" as "vendor lock-in". This phrase is normally reserved for use when there is a vendor that one must pay in order to continue to use a service, not merely cases where there is some difficulty or annoyance involved in changing something.
