To answer your question properly, we really need to know what your playing scenario is likely to be. From what you've posted, you're primarily playing for the enjoyment of it, not necessarily for gigs. That's a big distinction.
If you're playing for yours and your bandmates enjoyment, expanding your versatility probably isn't terribly important. Skip what you don't enjoy, or don't feel you can play because of the technical aspects.
If you plan on gigging, that's a whole other discussion. You need to categorize what kind of gig... bar gigs, concert style performances, etc.
My experience is from the bar band perspective, The mission is to play songs the patrons like, and will dance to. First priority. (I have to remind the band leader about that occasionally, lol.) As such, if you want to work a lot, you need to play stuff you don't necessarily like. At least most of us do, lol. I like to find ways to make what I play more interesting in some of those basic songs, without over playing.
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To the original point, if you plan on trying to work a lot, it's better to be able to incorporate stuff from different styles of music.. Even if you don't go deeply into those styles, being able to emulate at least parts of it is useful.. And you can find yourself using some of that stuff in other songs, outside of those genres, to make your performances more varied. (Which to me, is interesting. Wagon Wheel can only go so many ways in a bar, but sprinkling in different small things is fun. At least to me.)
About the age and time constraints... Our band will play over 100 shows this year, mostly basic bars and clubs. The youngest member of our band is 56. Two more are 62, another 71 and one more at 72. Three of us have large time commitments like you, so time to work on material can be limited. We don't have the time to rehearse, and our catalog is close to 300 songs now, not counting the chestnuts that we don't ever play but can pull out if need be. (Johnny B Goode, etc) If there is a song suggested that one of us cannot reasonably do, we will table that thought and move on to something else. But we will make a good faith effort to work on it first, to see if it's withing our capability. We don't go for simple songs, for the sake of simplicity. We go for songs that we think will work for our venues and typical audience. If its a challenge, so be it. If its simple. So be it. We've had a few that we thought we had down well enough, but never seemed to click when playing out. We purge it, and keep on moving on.
Last year, I went to a drum clinic with Mike Mangini, of Dream Theater. (Actually just after he was replaced in DT, but that's where people will know him from.) Very high level, technical stuff. His clinic wasn't all aimed at that style, but a lot of what he was talking about was referenced from that vantage point. I'll never play anything like that style of music, and certainly not with all those various time signatures and such. But I wanted to try and pick up some stuff that he was teaching, so that I could try and apply it to what I do.
I never played country music at all until I played in this band. When I was a young man, I thought is was all simple, easy songs about a guys dog leaving and his truck dying, etc
I have quickly learned that a lot of the newer country stuff is not as simple as one might think. And learning that was fun. Plus, we have added a couple older, more traditional country songs, and learning the basics of that is quite useful for other things, too.My advice? Don't limit yourself. Unless you enjoy sitting in the back, quietly playing boom-chick while the band does their thing, try and get into whatever you're playing, and make it interesting for the audience, and for you. Different styles make for more choices.
