I'm with walt on this. It's your money so you can do what you want, but it seems silly to say what you are currently doing is not market timing.
Fine, call it market timing. The label is irrelevant and the quotes from wiki-whatever are pedantic. I pulled out of the market once in my life and haven't gotten back in yet. If that's market timing, I'm timing the market. I see no shame in that label or strategy. Stupidity? Maybe. History will be my judge, but as I said before, I'll happily jump back when even if SP 500 is at 3500 provided that there's some modicum of normalcy (pandemic, fundamentals, earnings, debt, etc) -- and normalcy, in my view, is a low standard. I stayed in the market through 1998-2019 (I didn't change a thing, i.e., monthly investments in SP500 index, including 2007-10).
RE vaccines: The time, energy, and money going into vaccine development is impressive. Realistically, if one is available in December, that would exceptional. From what I've read, it seems Feb. - June is probably a more realistic time frame in the optimistic world. In the pessimistic world, it could be over 2 years. I agree that the past coronaviruses aren't good benchmarks because there was far less interest in developing a vaccine.
And then, of course, once it's developed, distributing it to achieve herd immunity will be challenging, both in terms of numbers and both in terms of the (growing?) number anti-vaxxers who see it as Bill Gates conspiracy to take over the world. But, I see that as a speed bump in the larger view of the road ahead.
Re markets: I think we all agree that the prices are way overvalued today and that that has been the case for several years now (and periodically throughout time). In the past, those over-values were based on outlooks of growth. And I see the argument that as soon as this pandemic is behind us, the economy will enter super charge mode. I think there are a lot of predictions/bets that that will occur in the 4th quarter of this year, maybe even the third. I personally think that that is too optimistic. And if I'm wrong, that would be excellent news. There's a ton of suffering happening these days and it's disheartening, bordering on depressing, to read the news each day.
As for cruise ships, yes, of course they're reporting that bookings are doing fine. Anyone who didn't think they'd actually get a refund or didn't care for one, told the cruise companies to rebook for later in the year or 2021. Some are seeing the super cheap offerings and the opportunity to cancel later and saying, why not, count me in. My friend didn't officially cancel her May 25th trip to Italy until May 15th because Air Italia offered her that. My point is that I would read very little at this point in time into late 2020 bookings given the realities of group social gatherings and group travel. Anyway, I just used cruise stocks to as the poster child for today's market insanity. Maybe there are better examples.
Good luck, everyone.