I was one of those people racing every weekend, sometimes two a weekend. So it's left a gap in my life.
All races until early June have been postponed, after that there are a couple still accepting registrations in late June and July but surely they will be postponed too. I look at the times they have been postponed to, mostly in November/December, and wonder how are they going to be allowed to go ahead even then? You would either need a situation where the country has zero or next to zero current infections, which seems unlikely anywhere, ever again, or you would need some major overhauls to how races have always been run. It seems likely to me that if marathons are going to continue to exist, they're going to require staggered starts of maybe 10 people at a time, where you are not really racing with people alongside you, rather against the clock. I've done a triathlon that employed this method so that too many people weren't swimming at the same time (they didn't have enough jetskis to ensure everybodies safety). For the people racing for prizes that might work, but for the people who are just running for fun it would take away a lot of the experience and comradery.
Or would masks at the start, temperature checks, sanitiser everywhere etc be enough?