EDIT to add: Always remember with solutions like this that the adversary isn't always the NSA and so on. The Tor users' page lists all kinds of people who need help against foes with limited budgets or knowledge who might not be able to break Linux or Tor.
Intel didn't release a mobile 64bit CPU until 2006/7 with Core 2 Duo.
Also the initial implementations of Intel64/EMT64 lack certain functions so even tho they technically support 64bit they might lack certain other features that are required by modern operating systems.
So overall if you have a 10 year old laptop you might not be able to use Tails 3.0.
I guess privacy is only for the rich.
I guess you could use an older version of Tails but I imagine this would become less and less secure as more and more vulnerabilities are found.
About time.
If they don't have any usage data, I think, they should provide old version and support it with critical security updates. If they have usage data, it depends, I guess.
If you're someone buying burner laptops these machines, which are very cheap, are now probably not a good idea.
I remember upgrading from 32-bit to 64-bit in-place a few times, which is a bit fiddly but not impossible with Debian. I wrote up a couple of guides once upon a time, but right now I can just find this old wiki-page discussing the process:
* Tails 3.0 works on 64-bit computers only and not on 32-bit computers anymore. Dropping hardware support, even for a small portion of our user base, is always a hard decision to make but being 64-bit only has important security and reliability benefits. For example, to protect against some types of security exploits, support for the NX bit is compulsory and most binaries are hardened with PIE which allows ASLR.
* Update Tor Browser to 7.0 (based on Firefox 52 ESR) which is multiprocess and paves the way to content sandboxing. This should make it harder to exploit security vulnerabilities in the browser.
What do you guys think about dropping 32-bit?