You could raise the difficulty...raise the planet count...raise the galaxy size.

Technically speaking, lowering the research speed will prolong your game, but it might not necessarily have you at a higher tech level when the game finishes, which appears to be your complaint.  It's also not exactly a good idea for TA because TA techs cost more anyway, even when the XML values are the same-particularly offensive techs, but really, all across the board, and inflation is worse, and starts earlier.

Most of us disable tech victory-it's really probably easier than it should be.  If memory serves, not really much more expensive than maxing out a single weapon tree (depending on whether you count the prerequisite research structures),and that's in DA, where techs are somewhat cheaper, overall.  Even influence victory poses an actual challenge compared to it, IMHO.

On the subject of alliances, I've found evidence to suggest that the AI may be unwilling to form alliances with other AI races until a certain time point. While I have never had anything to positively confirm this, I've seen the good AIs form alliances at the beginning of game year 7 again and again, so I increasingly suspect that may have something to do with it.

I've had games in TOA go on for quite a while. It would be nicer if I could get better weapons once in a while without having to sacrifice other research fields, but I've never really had a problem with games ending prematurely - though I will note that it is far too easy to win a diplomatic victory as a Super Diplomat unless you are a complete warmonger at the same time. My personal longest game lasted 18 game years, but that was back on the original Dread Lords, where it was a lot harder to get alliances (and I could have won well before that if I had simply wiped out the guys who wouldn't form an alliance). My longest game where things stayed interesting until the end was 12 years on DA.

I'm doing better getting longer games now by increasing map size, turning off research/ascension victory and a few other things. The only problem now is that the AI personality differences are a bit too dramatic. The Drengin, Thalan and a couple others NEVER expand and get steamrolled by the Terran/Altarian (main offenders) every single time. So then 1 AI rolls through the entire galaxy and becomes a juggernaught to which no one can stand up to. I think if the problem AI civs would expand properly, things would be a little more balanced late game since no one AI would get too powerful. I may try to set the AI personality to Terran/Altarian for those races and see if it changes anything. Poor Drengin are so laughable every game because they have 2 planets and that's all. Has to be a bug or something because he also had 50 ships parked outside of his home planet doing nothing. Could have rolled anyone but instead just sat there. Very disappointing.

Yeh totally strange about the Thalan. It isn't as frequent as the poor Drengin but many times I see the MASSIVE Thalan home planet and...that's all. Gonna switch up the personalities for sure (I too use the modified tech trees) and see where that goes.

AI personality 10 is bugged, which AI uses that one?

As Sole Soul suggested, increasing the difficulty level is likely the simplest solution.  You might also disable the random AI selection and choose the AIs so as to avoid the pushovers who are bugged.

I did not buy ToA because of the many reports of AI failures to expand or build, and I did not want to tinker with things like editing AI personalities as a partial work-around.  If they fix ToA in a patch so that I can play it w/o having to do work-arounds, I might still buy it.

If you want to fight for your "life" and not win before the late game, try DA on Suicidal in the largest DA galaxy size with all abundant settings.  However, if you do, I recommend disabling the research victory, but for your protection, not to help the AIs.

Each player prefers slightly different game set-ups.  My most recent favorite was DA, Suicidal, largest galaxy, all abundant, ascension victory off, 5 or 6 majors and max minors.

The Altarians (and a few other races besides) will only pursue space weapons if someone develops missile weapons.  It's a bug in the tech trees.  If you check out the modding forum (if you like playing with mods that is) you'll find something to fix that.

It seems to me like a common problem in Strategy games,  how sometimes a race that is usually powerful can just be ruined by the luck of where it starts out, or how many enemies surround them. In my current game, the Thalan are slowly sweeping the board, but in previous games, they have always been stuck on a few planets, unable to colonize in the face of opposition on all sides.

Reminds me of SMAC, where how peaceful the game would be usually depended on whether Miriam and Yang were stuck on a barren rock together...

Can I fix that bug without using your mod? You have done a great job, but I just don't like how your tech tree is complicated and hard to read.

That and the fixed EXE makes for one hell of a game.