As one who enjoys repairing gear rather than replacing it, I certainly get what you're saying. But... an entire bass head that weighs 2.5 pounds and fits in my gear bag was just too tempting, and has been utterly reliable for years. Speakers have gotten proportionately lighter too, thanks to modern magnets, though not much smaller. Granted, historical bass amps are heavier than guitar amps to begin with, and the weight savings is more appreciable.

In response to other posts about repair, high quality tube guitar amps are actually extremely reliable if not abused, and some component replacement that is done prophylactically (e.g., re-tubing and re-capping) is often unnecessary.