Foundry 2 is great especially with the expansion packs Potion and Thunder. I don’t think you need to be in a hurry to get off of it necessarily. There is an enormous amount of Stacks today that fill in any shortcomings of Foundry.
For an example Foundry’s angle stack wasn’t quite what I needed so I found a third party tool that worked really well. It will probably take a while for elements to build up a third party market that is at where Stacks is today.
Foundry, v2 and especially v3, will be OK for quite some time.
According to Elixir themselves (about a month ago when their forums were still up), Alloy is a different story - if you have Alloy based projects, it might be a good idea to look for a replacement.
A good replacement for Alloy (with online editing of articles and blog posts) is EasyCMS by Weaver’s Space (about $50).
Yes, Easy CMS doesn’t do a Blog. So you would have to go the TCMS-road which I only can recommend. I have around 30 to 40 client sites with TCMS and they love(!) it…