So we see lots of posts about roll your router via ddwrt, tomato, merlin, etc why not the equivalent for modems? I am thinking this would be ideal to roll into pfsense on a VM Of course I don't know ...

Personally if I wanted to do a software router, especially as a virtual machine, I would look at a simple small server (tower or rack, depending on my environment). That or a small business oriented ...

Upgrading from your basic router, whether it was supplied by your ISP or not, is a huge step towards building a more resilient home network. You could get an off-the-shelf router or take the plunge ...