True. But I would highly recommend that you consider "how to sell a B2B product" before considering legacy segments like ERP. Its non-trivial to build a new product from scratch in these spaces but there is an opportunity to build SaaS version of ERP products for small and mid-market customers. See these examples: http://www.coupa.com and http://www.nurturehq.com. Both are good products with large markets, are completely hosted and don't involve any legacy integrations which can be a killer.
However, all such products do require a systematic sales team/plan/process including inbound/outbound/inside sales kind of approaches to build revenue.