I just pulled up a Houston Astros Schedule here:
You're right, there aren't a lot of televised games. I think that this may be more of an issue with the MLB Baseball Association over any TV vendor.
I would recommend contacting MLB at their website:
https://www.mlb.com/ (Contact info is way down the bottom of the page.)
Mention why there aren't more Astros games? Are you in the Houston area? Maybe that is something that the MBA can work on for this and future seasons?
Why are Astros MLB games rarely on Spectrum? We should be able to watch the World Champions.
If you are in-market, the Astros will be on AT&T Sportsnet Southwest (formerly Comcast Sportsnet Houston). You must be in what MLB deems Houston home territory to get the games on this channel and not have the game itself blacked out.
If you are out-of-market, you will need to subsccribe to MLB extra innings to get Houston Astros games.
The exception are games carried nationally on ESPN or MLB Netowrk.
Your only beef with Spectrum would be if they are in a carriage dispute with AT&T Sportsnet Southwest. If you are in-market and this channel is not carried, you will not be able to get Houston Astros games.
If you are out-of-market, you'll have to pay for MLB Extra Innings (or MLB.tv). I'd recommend MLB.tv because they'll be guaranteed to have HD feeds. MLB Extra Innings may not (in your market) be in HD for all games.
You can complain to MLB about the lack of national coverage for the Astros, but I am sure that ESPN has the data to back up which teams will get them the best return on the rights fees they paid to air games. Like the Dallas Cowboys, New England Patriots, and Pittsburgh Steelers, the Yankees, Red Sox, Cubs, and Cardinals will always be featured "nationally".