Re: Email forwarding services are passé
Any email forwarding is easily coped with, and SPF can be simply added (it's IET's job to say what mailserver can claim to be from their domains, that's it - they could just leave an open record on it or offera basic SMTP sender with auth).
And envelope-rewriting and forwarding is supported by just about every domain-name host out there with email-forwarding. I forward ALL my public emails (which I use heavily for everything, personal and business, for 20+ years) to a GMail (ultimately, but that's unpublicised and can be changed in seconds) which I use as my actual method to collect and read and reply to those emails.
I also run my OWN forwarding server to do just that as secondary, to handle more critical domains, etc.. It's Postfix and maybe an hour of config for anyone familiar with Linux at all. That forwards to and isn't blocked by Google etc. unless it's quite obvious spam. My own grey-listing, SPF-checking, DKIM-checking, etc. spam filter blocks WAY MORE than GMail does, and it never touches even fresh incoming addresses at my domains (e.g. email@example.com) that haven't ever seen an email prior.
Their reasoning isn't based on that because it's hard. It's just an expense and liability that they don't need. Personally, I'd ask people for £100 per address per year and then bolt it into Google Apps for those customers who want to pay to retain it. Would take long at all, and no GDPR liability as you literally never touch their email. But I can perfectly understand why they wouldn't want to, it's just not their job.