No viable alternative?
1. Buying metal/plastic minis and painting them. This worked just fine for me until Wizards brought out their plastic minis (and I didn't start buying them until Angelfire/underdark since I didn't like the early sculpts and paint jobs. Six years in the 3e era and a good ten years before that seems plenty viable to me.
2. Buying metal or plastic minis and using them unpainted. It's not visually as appealing but it works just fine. I've seen lots of people do this at conventions, etc. I never liked it much but it works.
3. Counters. Fiery Dragon's creature counters and other cardstock counters are perfectly sufficient for the needs of D&D players. If I hadn't had a large minis collection from the 1e and 2e days, I probably would have gone that route.
4. Nonrepresentational counters. One of the people I play with regularly uses little plastic monkeys and ducks like you would put on the end of a pencil. If no-one gives him a representational mini to use, he's the monkey with a fez. If we don't pull out minis for the bad guys, they're ducks or monkeys. Pennies, glass beads (like you get at a craft store), dimes, and nickles work just fine as long as you have sufficient differentiation to be able to tell the orc warriors from their cheif and from the shaman. Games Workshop's large monster bases are quite good stand-ins for large monsters and cut out 3x3 or 4x4 bits of paper work for huge and gargantuan monsters.
There are plenty of options to maintain the tactical detail of map based D&D combat without using WotC's pre-painted minis. For my part, though, I like the minis.