The way I looked at it was % of games I've bought that I've actually finished
On the Switch right now I've just passed the 80 games mark, but of those I can say I have completed around 20 titles (100% done everything in them.... far beyond that in some cases) which means of my games I have a 25% completion rate and many more titles on the go towards that point.
On my ps4 from picking up far too many games in the systems first year and from psn+ I think I have over 250 titles on my psn account for it... of those I would wager that I have actually 100%'d far less than 20 games which means a completion rate of far less than 10%
From that fact I gauge that a game on the Switch is 2.5x more likely to actually get played through than its ps4 counterpart because of the ability to pick it up and take it with me if I'm going somewhere as well as the dock connected to my projector in the sitting room just like my PS4 is, but... that means that if a game is in the region of double the cost on the Switch than the ps4, I will still likely get more value out of buying it on the Nintendo machine, ie Yooka Laylee on the PS4 was €15 recently in a psn sale, the Switch version was €30 but with a 2.5x higher chance of being played I think that 30 will more likely end up as being hours of fun than the cheaper PS4 option
Yeah, I feel ya. I cannot gauge myself the same way as I only play one single player game at any given time. I like to at least complete the main story and side content to my satisfaction before starting another game. Multiplayer is a bit different, but there is less story involved in those games.
So when God of War came out, it was all I played until I got the plat. When Breath of the Wild came out, I played 130 hours before even touching another single player game. My general rule is if I start it, I finish it. So my total hours of available playtime is what dictates my choice.